Estimation of microphytobenthic resuspension fluxes in a shallow lagoon in Hokkaido, Japan

We conducted field sampling in a subarctic shallow lagoon (Hichirippu Lagoon) in the eastern part of Hokkaido, Japan. We investigated the chemical composition of the water column, sediment, and sinking particles collected by the sediment trap. The standing stock of chlorophyll a (Chl-a) in the water column and surface sediment were 0.4 to 9.3 and 35.9 to 184 mg m−2, respectively. Using stable isotope analysis, the contribution rate of microphytobenthos to the sinking particles was found to range from 63 to 74%. The average Chl-a content in the sinking particles was significantly lower than that of the water column. Our results suggest that the contribution of phytoplankton present in the water column to the Chl-a collected in the traps is likely to be negligible. We assumed that the Chl-a fluxes obtained in this study were microphytobenthic resuspension fluxes. The daily flux of Chl-a accounted for 47.0 to 1,270% of the total standing stock of Chl-a in the water column. The mean relative percentage of daily Chl-a flux divided by the standing stock of Chl-a in the sediment was 6.5%, which indicates that approximately 7% of the microphytobenthos present in the sediment was resuspended, and 93% of the total succeeded at escaping the winnowing action. Although the resuspension phenomenon had little effect on the population of microphytobenthos, the resuspended microphytobenthos had a major impact on the total micro algal biomass in the water column. This is the first direct estimate of microphytobenthic resuspension flux in shallow estuaries

Chronic Subdural Hematoma Associated with External Decompression for Acute Traumatic Intracranial Hematoma: report of two cases

A report is presented on two cases of chronic subdural hematoma which occurred after craniotomy, removal of the hematoma and external decompression for traumatic intracranial hematoma. As for the pathogenesis of chronic subdural hematoma of these two cases, these chronic subdural hematomas were considered to have originated from the subdural collection of mixed fluid of cerebrospinal fluid and blood caused by tearing of the arachnoid on head injury or craniotomy in the space between the brain and dural plasty. Opening and irrigating the hematoma cavity proved adequate as treatment at cranioplasty

Clinical characteristics and risk factors of enterococcal infections in Nagasaki, Japan: a retrospective study

Background: Enterococcus spp. are particularly important etiological agents of nosocomial infections. However, the clinical characteristics of and risk factors for enterococcal infections in clinical settings are poorly understood. Methods: The sample included patients with Enterococcus spp. infections detected from clinical samples at Nagasaki University Hospital between 2010 and 2011 and patients with enterococcal colonization (control patients). In this retrospective study, the risk factors for enterococcal infections were analyzed by comparing infected and control patients via multivariate logistic regression. Results: A total of 182 infected (mean age, 64.6±18.2years; 114 men) and 358 control patients (patients with enterococcal colonization) (mean age, 61.6±22.4years; 183 men) were included. Enterococcal infections were classified as intraperitoneal (n=87), urinary tract (n=28), or bloodstream (n=20) infections. Cancer and hematological malignancies were the most common comorbidities in enterococcal infections. Carbapenem and vancomycin were administered to 43.8% and 57.9% of patients infected with Enterococcus faecalis and Enterococcus faecium, respectively. No vancomycin-resistant enterococci were isolated. Multivariate analysis identified abdominal surgery (odds ratio [OR], 2.233; 95% confidence interval [CI], 1.529-3.261; p?0.001), structural abnormalities of the urinary tract (OR, 2.086; 95% CI, 1.088-4.000; p=0.027), male sex (OR, 1.504; 95% CI, 1.032-2.190; p=0.033), and hypoalbuminemia (OR, 0.731; 95% CI, 0.555-0.963; p=0.026) as independent risk factors for enterococcal infections. Multivariate analysis showed abdominal surgery (OR, 2.263; 95% CI, 1.464-3.498; p?0.001), structural abnormalities of the urinary tract (OR, 2.634; 95% CI, 1.194-5.362; p=0.008), and hypoalbuminemia (OR, 0.668; 95% CI, 0.490-0.911; p=0.011) were independent risk factors for E. faecalis infection. Finally, immunosuppressive agent use (OR, 3.837; 95% CI, 1.397-10.541; p=0.009) and in situ device use (OR, 3.807; 95% CI, 1.180-12.276; p=0.025) were independent risk factors for E. faecium infection. Conclusions: These findings might inform early initiation of antimicrobial agents to improve clinical success

The hrp genes of Pseudomonas cichorii are essential for pathogenicity on eggplant but not on lettuce

Pseudomonas cichorii causes necrotic lesions in eggplant and rot in lettuce. Through transposon insertion into P. cichorii strain SPC9018 we produced two mutants, 4-57 and 2-99, that lost virulence on eggplant but not lettuce. Analyses showed that a transposon was inserted into the hrpG gene in 4-57 and the hrcT gene in 2-99. Nucleotide sequences of the hrp genes of SPC9018 are homologous to those of Pseudomonas viridiflava BS group strains. The pathogenicity of 4-57 on eggplant was restored by transformation with an hrpF operon, originating from either SPC9018 or the BS group member P. viridiflava strain 9504 (Pv9504). These data suggested the involvement of hrp genes in the pathogenicity of SPC9018 on eggplant, and functional conservation of hrpF operons between SPC9018 and Pv9504. Both the hrpS mutant and the hrpL mutant were unable to cause necrotic lesions on eggplant leaves but retained their pathogenicity against lettuce. These results suggest that the pathogenicity of P. cichorii is hrp-dependent in eggplant, but not in lettuce

Possibility of direct utilization of seagrass and algae as main food resources by small gastropod, Lacuna decorata, in a subarctic lagoon, Hichirippu, eastern Hokkaido, Japan with stable isotope evidences of carbon and nitrogen

The small gastropod, Lacuna decorata Adams, living on macrophytobenthos or surface sediment, is one of the most dominant species of macrozoobenthos in Hichirippu lagoon covered with seagrass and macroalgae, eastern Hokkaido, Japan. We measured the standing stocks of primary producers and macrozoobenthos, and determined the stable carbon and nitrogen isotope ratios of the primary producers and L. decorata. With these results, we identify the main food items for L. decorata and discuss the feeding strategy of the small gastropod. This gastropod occupied about 64% in density and about 25% in biomass of the macrozoobenthos at all six sampling stations in the lagoon. It occurred densely on the surface of the sediment with dense patches of benthic microalgae (BMA), which contained extremely high levels of Chl.-a between 84 to 226 mg m−2 throughout the period of this study. Nevertheless, the stable isotope signatures of carbon and nitrogen of this gastropod clearly show the direct utilization of organic matter derived from seagrass, Zostera japonica, in the areas where the seagrass luxuriated. However, it shows also a flexible feeding strategy in food preference. It fed green algae such as Ulva pertusa and Urospora wormskioldii in the areas where the seagrass grew scarcely

Reevaluation of the nutrient mineralization process by infaunal bivalves (Ruditapes philippinarum) in a shallow lagoon in Hokkaido, Japan

Previous estimations of nutrient mineralization in the water column by infaunal bivalves might have been overestimated because of underestimation of the uptake process by microphytobenthos in the field. We conducted field surveys of environmental conditions and quantitative sampling of Ruditapes philippinarum in a shallow lagoon system (Hichirippu Lagoon, eastern Hokkaido, Japan) in August 2006. We recorded the spatial distribution pattern and the molar ratio of dissolved inorganic nutrients to determine the limiting nutrients for microphytobenthos, to evaluate the input and output of nutrients at the entrance of the lagoon station, and to estimate potential nutrient mineralization by R. philippinarum. Our aim was to reevaluate the nutrient mineralization process by infaunal bivalve species. In this study, the mean standing stock of microphytobenthos inhabiting surface sediment (5 mm thick) on the tidal flats was 100 times higher than that of phytoplankton (1 m depth). Low N/P and high Si/N ratios (mean = 2.6 and 17.6, respectively) near the entrance of the lagoon compared to those of microphytobenthos (N:P:Si = 10.1:1:18) clearly suggest N deficiency. The flux of NH4-N coming into the lagoon was 3.4 kmolN d^[-1], and the flux out was -3.7 kmolN d^[-1]. Thus, assuming that there would have been no phytoplankton and microphytobenthos uptake during the day, 0.3 kmolN d^[-1] of NH4-N was produced within the lagoon. However, the NH4-N mineralization rate of the clams has been estimated to be approximately 7.7 ± 6.8 kmolN d^[-1]. Thus, 96% (7.4 kmolN d^[-1], i.e., 7.7 kmolN d^[-1] minus 0.3 kmolN d^[-1]) of the NH4-N mineralized by the clam was consumed by microphytobenthos. In contrast, if all the NH4-N inflow (3.1 kmolN d^[-1]) was consumed by the microalgae before outflow, 52% (4.0 kmolN d^[-1], i.e., 7.7 kmolN d^[-1] minus 3.7 kmolN d^[-1]) of the NH4-N mineralized by the clams should have been consumed by microphytobenthos. Microphytobenthos on the tidal flats (11.3 ± 11.8 kmolN) used all of the surplus nutrients (between 4.0 and 7.4 kmolN d^[-1]), and the temporal division rate [=(NH4-N uptake)/(standing stock of microphytobenthos)] of microphytobenthos would have to be between 0.35 and 0.65 d^[-1]. Residual NH4-N (0.3-3.7 kmolN d^[-1]) was the water column source and accounted for 12-148% of NH4-N in the water column near the entrance of the lagoon (2.5 ± 1.4 kmolN) per day. This is the first field-based observation with a quantitative evaluation of nutrient mineralization by infaunal bivalves and nutrient uptake by microphytobenthos