Effect of Bacillus subtilis Zeolite Used for Sediment Remediation on Sulfide, Phosphate, and Nitrogen Control in a Microcosm.

Eutrophication is an emerging worldwide issue concerning the excessive accumulation of various pollutants in sediments, owing to the release of industrial or household wastewaters to coastal areas. The coastal sediment of Goseong Bay in the Republic of Korea is organically enriched with pollutants, including heavy metals, sulfide, phosphate, and ammonia. Microbial remediation and capping techniques have been suggested as effective routes for sediment remediation. In this study, Bacillus subtilis zeolite (BZ) was used as a sediment capping material, and effective remediation of coastal sediment was observed in a 40-day laboratory microcosm experiment. A significant decrease in the sediment water content and reduced concentration of acid volatile sulfide were observed in the BZ-capped sediment. In the overlying water and pore water, significant decreases in phosphate and dissolved inorganic nitrogen (DIN; NO2-N + NO3-N and NH4-N) concentrations were observed in the BZ-treated experiment. Based on our findings, we conclude that BZ could be an effective capping material for coastal sediment remediation.

Assessment of the Dynamics of Microbial Community Associated with Tetraselmis suecica Culture under Different LED Lights Using Next-Generation Sequencing.

Tetraselmis is a green algal genus, some of whose species are important in aquaculture as well as biotechnology. In algal culture, fluorescent lamps, traditional light source for culturing algae, are now being replaced by a cost-effective light-emitting diodes (LEDs). In this study, we investigated the effect of LED light of different wavelengths (white, red, yellow, and blue) on the growth of Tetraselmis suecica and its associated microbial community structures using the next-generation sequencing (NGS). The fastest growth rate of T. suecica was shown in the red light, whereas the slowest was in yellow. The highest OTUs (3426) were identified on day 0, whereas the lowest ones (308) were found on day 15 under red light. The top 100 OTUs associated with day 0 and day 5 cultures of T. suecica under the red and yellow LED were compared. Only 26 OTUs were commonly identified among four samples. The highest numbers of unique OTUs were identified at day 0, indicating the high degree of initial microbial diversity of the T. suecica inoculum. The red light-unique OTUs occupied 34.98%, whereas the yellow-specific OTUs accounted for only 2.2%. This result suggested a higher degree of interaction in T. suecica culture under the red light, where stronger photosynthesis occurs. Apparently, the microbial community associated with T. suecica related to the oxygen produced by algal photosynthesis. This result may expand our knowledge about the algaebacteria consortia, which would be useful for various biotechnological applications including wastewater treatment, bioremediation, and sustainable aquaculture.

Formation and germination of temporary cysts of Cochlodinium polykrikoides Margalef (Dinophyceae) and their ecological role in dense blooms.

While the initiation and development of dense bloom of Cochlodinium polykrikoides have been shown to be related to some environmental factors, little is known about the ecological role of the formation and germination of temporary cysts, nor of their significance for the rapid expansion of dense regional-scale blooms. This study examined the factors affecting the formation and germination of temporary cysts of C. polykrikoides, and provides details about the germination process. In the laboratory experiments, C. polykrikoides produced the chain-forming temporary cysts that are immobile and surrounded by a hyaline membrane. The encystment experiment indicated that darkness induces the formation of chain-forming temporary cysts, consistent with field observation of morphology and fluxes of temporary cysts. Germination occurred twice from a single four-celled temporary cysts within 24h after exposure to light, and the germlings appeared as two-celled chain-forming vegetative cells. The germination behavior of temporary cysts of C. polykrikoides differs from that of other dinoflagellates, and this may be a survival strategy for the maintenance of population size during dense blooms.

Growth and uptake kinetics of nitrate and phosphate by benthic microalgae for phytoremediation of eutrophic coastal sediments.

In the present study, the effect of monochromatic light (blue, yellow and red) and mixed wavelength on the nutrient uptake and growth kinetics of benthic microalgae Achnanthes sp., Amphora sp., Navicula sp. and Nitzschia sp. were investigated. The maximum uptake rate (ρmax) for nitrate and phosphate obtained by short-term experiments were high in the order of blue, mixed, red, yellow wavelength, and among the 4 benthic microalgae, Nitzschia sp. was the highest ρmax. The half-saturation constant (Ks) was higher than other taxon. The specific maximum growth rate (µmax') and minimum cell quota (q0) for the nitrogen and phosphorus-limited condition, Nitzschia sp. showed the highest µmax' and q0 values among the 4 benthic microalgae. These results suggest that the benthic microalgae are adapted to high nutrient concentration. In particular, Nitzschia sp., which have a higher capability of storage and uptake, may be a useful species for phytoremediation.

Ecological significance of alkaline phosphatase activity and phosphatase-hydrolyzed phosphorus in the northern part of Gamak Bay, Korea.

We investigated the ecological significance of alkaline phsophatase (APase) and alkaline phosphatase-hydrolyzable phosphorus (APHP) in the northern part of Gamak Bay, Korea. APase activity was detectable throughout the year, and dissolved inorganic phosphorus (DIP) concentration and APase activity are highly correlated and can be regarded as an indicator of DIP-limiting conditions. Also, a strong linear positive correlation between APase activity and Chl a concentration indicated that the major part of APase activity may have been induced by phytoplanktons. The APHP proportion in dissolved organic phosphorus (DOP) was above ca. 30% from winter to spring and below ca. 15% from summer to autumn due to freshwater discharge and uptake by phytoplankton. APHP may play an important role in species competition in coastal area such as northern part of Gamak Bay where DIP is limiting. Thus, APase induction by phytoplanktons may be ecologically significant, allowing dominance by these organisms under DIP-limiting conditions.

Reconstruction of historical nutrient levels in Korean and Japanese coastal areas based on dinoflagellate cyst assemblages.

Dinoflagellate cysts acquired from sediment cores were analyzed in order to reconstruct historical nutrient levels in Gamak Bay, Korea and Ariake Bay, Japan. Dinoflagellate cyst assemblages in Gamak Bay were characterized by high proportions of heterotrophic cysts such as Brigantedinium spp., Protoperidinium americanum and Polykrikos cysts, which suggested that nutrients levels may have already been high before 1970s, and then increased further to the hypertrophic conditions of the 1990s. In contrast, dinoflagellate cyst assemblages in Ariake Bay were characterized by high relative abundances of Lingulodinium machaerophorum and Spiniferites spp., which suggested that nutrient levels in Ariake Bay had increased gradually since the mid 1960s, and may have been significantly enhanced by the mid 1980s. Dinoflagellate cyst assemblages reflecting environmental changes in the two bays are contrasting, perhaps due to different nutrient enrichment mechanisms. This suggests that the indicators of nutrient levels encoded in dinoflagellate cyst assemblages may exhibit site-specific information.

[Extrapancreatic tumors in intraductal papillary mucinous neoplasm of the pancreas].

BACKGROUND/AIMS: Intraductal papillary mucinous neoplasm (IPMN) of the pancreas has a favorable prognosis, but seems to be associated with a high incidence of extrapancreatic tumors. The purpose of this study was to evaluate the incidence and clinicopathological features of extrapancreatic tumors associated with IPMN. METHODS: Thirty-seven patients with IPMN of the pancreas, confirmed by surgical resection and typical findings of endoscopic ultrasonography and CT imaging between October 1, 1998 and August 31, 2006 were included. Seventeen patients were diagnosed with surgical resection and biopsy, and others by typical imaging findings of IPMN. These patients were examined for the development of extrapancreatic tumors. RESULTS: Of 37 patients with IPMN, 14 (38%) had 18 extrapancreatic tumors, and 10 (27%) had 13 extrapancreatic malignancies. Five, six, and two extrapancreatic malignancies had been diagnosed before, during, and after the diagnosis of IPMN. Gastric adenocarcinoma (3 patients, 23%) and colorectal carcinoma (3 patients, 23%) were the most common neoplasms. Other extrapancreatic tumors included lung cancer (n=2), prostatic cancer (n=1), renal cell carcinoma (n=1), cholangiocellular carcinoma (n=1), urinary bladder cancer (n=1), and gallbladder cancer (n=1), respectively. As benign tumor, there were two gallbladder adenoma, one gastric adenoma, one colonic adenoma and one benign ovarian cystic neoplasm, respectively. CONCLUSIONS: IPMN is associated with high incidence of extrapancreatic tumors, particularly gastric and colorectal neoplasms. Upper gastrointestinal endoscopy and colonoscopy should be done, and systemic surveillance for the possible occurrence of other tumors may allow early detection of extrapancreatic tumor in patients with IPMN.

Human application of a metallic stent covered with a paclitaxel-incorporated membrane for malignant biliary obstruction: multicenter pilot study.

BACKGROUND: Paclitaxel, with its antitumor effect, may improve the function of metallic stents used for biliary drainage. However, clinical studies that use metallic stents covered with a paclitaxel-incorporated membrane (MSCPM) in the biliary tract of human beings have not been previously carried out. OBJECTIVE: To evaluate the safety and efficacy of an MSCPM for patients with malignant biliary obstruction. DESIGN AND SETTING: A case series that includes 4 endoscopy centers. PATIENTS: From July 2003 to August 2006, a total of 21 patients diagnosed with unresectable malignant biliary obstruction. INTERVENTION: Endoscopic placement of an MSCPM. MAIN OUTCOME MEASUREMENTS: Stent occlusion, complications, stent patency, patient survival, and the periodic mean concentration of paclitaxel in the blood. RESULTS: Occlusion of the MSCPM was observed in 9 patients and was caused by bile sludge or clog in 4, tumor overgrowth in 3, and tumor ingrowth in 2. Complications included obstructive jaundice in 6, cholangitis in 3, and 1 patient showed stent migration with cholecystitis. The mean patency of a MSCPM was 429 days (median 270 days, range 68-810 days) and cumulative patency rates at 3, 6, and 12 months were 100%, 71%, and 36%, respectively. The mean survival of patients was 350 days (median 281 days, range 68-811 days). The highest concentration of paclitaxel in the blood was found between 1 and 10 days after insertion. LIMITATIONS: Small number of patients and low rate of pathologic diagnosis. CONCLUSIONS: The endoscopic insertion of MSCPM is technically feasible, safe, and effective in patients with malignant biliary obstruction. In addition, MSCPM may exert local antitumor activity because of the steady release of paclitaxel.

5-Fluorouracil and Cisplatin (FP) with Concurrent Radiotherapy for Locally Advanced Head and Neck Cancer.

PURPOSE: The combination of chemotherapy and radiotherapy is emerging as the new standard modality for the treatment of locally advanced head and neck cancer, due to the inherent functional and cosmetic sequelae associated with its surgical management. Combination chemotherapy with 5-fluorouracil and cisplatin (FP) is one of the most active regimens for the head and neck cancer. Furthermore, both agents are known to act as radiosensitizer. This study was conducted to determine the efficacy, feasibility, and the toxicities of concurrent FP chemotherapy with radiotherapy. MATERIALS AND METHODS: Patients with histologically proven locally advanced head and neck cancer (T3-4 or node positive) were enrolled in the study. Patients received 5-fluorouracil, 1,000 mg/m2/day, continuously for 4 days, and cisplatin, 75 mg/m2, on day 1. This regimen was given every four weeks. The radiotherapy (45 Gy) was started on day 1 of the first cycle, and administered in 25 fractions. Following a three-week interval, the radiotherapy was resumed on day 1 of the third cycle of chemotherapy, and administered in 15 fractions (27 Gy). RESULTS: Of the 31 eligible patients included, 28 were able to be evaluated for the tumor response. The response rate for the 28 patients was 93% (16 complete responses, 10 partial responses). Disease free survival for the 16 complete responders was 37 months (median, 1 ~41 months), with a median follow-up time of 31 months. The 1-, 2-, and 3-year survival rates were 82%, 69%, and 63%, respectively. Regarding the feasibility of this treatments, only nineteen patients (61%) received the complete courses of scheduled treatments. The median duration of admission for all patients was 39 days. Grade 3 or 4 stomatitis were observed in 25 patients (83%) and appeared as the dose limiting toxicity of this regimen. CONCLUSION: Although FP chemotherapy with concurrent radiotherapy is toxic, it is an effective and relatively feasible treatment for locally advanced head and neck cancer. The majority of patients experienced severe stomatitis, which appeared as the dose limiting toxicity of this regimen.