Distribution of microplastics in bathyal- to hadal-depth sediments and transport process along the deep-sea canyon and the Kuroshio Extension in the Northwest Pacific

Understanding microplastic (MP) behavior in oceans is crucial for reducing marine plastic pollution. However, the complex process underlying MP transportation to the deep seafloor remains unknown despite the deep sea being considered its major sink. We focused on MP distribution in Sagami Bay (adjacent to highly populated areas of Japan), the plate triple junction connected through the Sagami Trough, and the abyssal plain immediately below the Kuroshio Extension. We observed the highest number of MPs in the abyssal stations, more than previously reported. The polymer types and aspect ratio of MPs in the abyssal stations significantly differed from those in the bathyal/hadal stations. The study suggests that MPs accumulated in the open ocean surface layer sink to the abyssal plains immediately below it, while MPs from land sources accumulate in the bathyal depth and are transported to the hadal depth near the coast through turbidity currents along the submarine canyon.

Microbial decomposition of biodegradable plastics on the deep-sea floor

Microbes can decompose biodegradable plastics on land, rivers and seashore. However, it is unclear whether deep-sea microbes can degrade biodegradable plastics in the extreme environmental conditions of the seafloor. Here, we report microbial decomposition of representative biodegradable plastics (polyhydroxyalkanoates, biodegradable polyesters, and polysaccharide esters) at diverse deep-sea floor locations ranging in depth from 757 to 5552 m. The degradation of samples was evaluated in terms of weight loss, reduction in material thickness, and surface morphological changes. Poly(L-lactic acid) did not degrade at either shore or deep-sea sites, while other biodegradable polyesters, polyhydroxyalkanoates, and polysaccharide esters were degraded. The rate of degradation slowed with water depth. We analysed the plastic-associated microbial communities by 16S rRNA gene amplicon sequencing and metagenomics. Several dominant microorganisms carried genes potentially encoding plastic-degrading enzymes such as polyhydroxyalkanoate depolymerases and cutinases/polyesterases. Analysis of available metagenomic datasets indicated that these microorganisms are present in other deep-sea locations. Our results confirm that biodegradable plastics can be degraded by the action of microorganisms on the deep-sea floor, although with much less efficiency than in coastal settings.

mTORC1 regulates phagosome digestion of symbiotic bacteria for intracellular nutritional symbiosis in a deep-sea mussel

Phagocytosis is one of the methods used to acquire symbiotic bacteria to establish intracellular symbiosis. A deep-sea mussel, Bathymodiolus japonicus, acquires its symbiont from the environment by phagocytosis of gill epithelial cells and receives nutrients from them. However, the manner by which mussels retain the symbiont without phagosome digestion remains unknown. Here, we show that controlling the mechanistic target of rapamycin complex 1 (mTORC1) in mussels leads to retaining symbionts in gill cells. The symbiont is essential for the host mussel nutrition; however, depleting the symbiont's energy source triggers the phagosome digestion of symbionts. Meanwhile, the inhibition of mTORC1 by rapamycin prevented the digestion of the resident symbionts and of the engulfed exogenous dead symbionts in gill cells. This indicates that mTORC1 promotes phagosome digestion of symbionts under reduced nutrient supply from the symbiont. The regulation mechanism of phagosome digestion by mTORC1 through nutrient signaling with symbionts is key for maintaining animal-microbe intracellular nutritional symbiosis.

Effectiveness of hierarchical Bayesian models for citizen science data with missing values: A case study on the factors influencing beach litter in Shimane Prefecture, Japan

Citizen science can play an important role in addressing the issue of marine debris. However, citizen science data are often composed of inconsistent methods compared to data collected by experts. In this study, we applied beach cleanup data, collected in different survey years at different survey sites, to a hierarchical Bayesian model to elucidate the factors affecting the distribution of beach litter. The results showed the model accounting for differences between years had a smaller Watanabe-Akaike Information criterion than the model that did not account for it, indicating better accuracy of the model. The amount of beach litter was influenced by current velocity and bay openness, and these effects varied across years. The results indicate that citizen science data, which may contain missing values due to various constraints such as economic and human resources, can make an important contribution toward solving marine debris issues by flexible statistical analysis methods.

Foraminifera and plastic pollution: Knowledge gaps and research opportunities

Plastic has become one of the most ubiquitous and environmentally threatening sources of pollution in the Anthropocene. Beyond the conspicuous visual impact and physical damages, plastics both carry and release a cocktail of harmful chemicals, such as monomers, additives and persistent organic pollutants. Here we show through a review of the scientific literature dealing with both plastic pollution and benthic foraminifera (Rhizaria), that despite their critical roles in the structure and function of benthic ecosystems, only 0.4% of studies have investigated the effects of micro- and nano-plastics on this group. Consequently, we urge to consider benthic foraminifera in plastic pollution studies via a tentative roadmap that includes (i) the use of their biological, physiological and behavioral responses that may unveil the effects of microplastics and nanoplastics and (ii) the evaluation of the indicative value of foraminiferal species to serve as proxies for the degree of pollution. This appears particularly timely in the context of the development of management strategies to restore coastal ecosystems.

In situ experimental evidences for responses of abyssal benthic biota to shifts in phytodetritus compositions linked to global climate change

Abyssal plains cover more than half of Earth's surface, and the main food source in these ecosystems is phytodetritus, mainly originating from primary producers in the euphotic zone of the ocean. Global climate change is influencing phytoplankton abundance, productivity, and distribution. Increasing importance of picoplankton over diatom as primary producers in surface oceans (especially projected for higher latitudes) is projected and hence altering the quantity of organic carbon supplied to the abyssal seafloor as phytodetritus, consequences of which remain largely unknown. Here, we investigated the in situ responses of abyssal biota from viruses to megafauna to different types of phytoplankton input (diatoms or cyanobacteria which were labeled with stable isotopes) at equatorial (oligotrophic) and temperate (eutrophic) benthic sites in the Pacific Ocean (1°N at 4277 m water depth and 39°N at 5260 m water depth, respectively). Our results show that meiofauna and macrofauna generally preferred diatoms as a food source and played a relatively larger role in the consumption of phytodetritus at higher latitudes (39°N). Contrarily, prokaryotes and viruses showed similar or even stronger responses to cyanobacterial than to diatom supply. Moreover, the response of prokaryotes and viruses was very rapid (within 1-2 days) at both 1°N and 39°N, with quickest responses reported in the case of cyanobacterial supply at higher latitudes. Overall, our results suggest that benthic deep-sea eukaryotes will be negatively affected by the predicted decrease in diatoms in surface oceans, especially at higher latitudes, where benthic prokaryotes and viruses will otherwise likely increase their quantitative role and organic carbon cycling rates. In turn, such changes can contribute to decrease carbon transfer from phytodetritus to higher trophic levels, with strong potential to affect oceanic food webs, their biodiversity and consequently carbon sequestration capacity at the global scale.

16S rRNA Gene Metabarcoding Indicates Species-Characteristic Microbiomes in Deep-Sea Benthic Foraminifera

Foraminifera are unicellular eukaryotes that are an integral part of benthic fauna in many marine ecosystems, including the deep sea, with direct impacts on benthic biogeochemical cycles. In these systems, different foraminiferal species are known to have a distinct vertical distribution, i.e., microhabitat preference, which is tightly linked to the physico-chemical zonation of the sediment. Hence, foraminifera are well-adapted to thrive in various conditions, even under anoxia. However, despite the ecological and biogeochemical significance of foraminifera, their ecology remains poorly understood. This is especially true in terms of the composition and diversity of their microbiome, although foraminifera are known to harbor diverse endobionts, which may have a significant meaning to each species' survival strategy. In this study, we used 16S rRNA gene metabarcoding to investigate the microbiomes of five different deep-sea benthic foraminiferal species representing differing microhabitat preferences. The microbiomes of these species were compared intra- and inter-specifically, as well as with the surrounding sediment bacterial community. Our analysis indicated that each species was characterized with a distinct, statistically different microbiome that also differed from the surrounding sediment community in terms of diversity and dominant bacterial groups. We were also able to distinguish specific bacterial groups that seemed to be strongly associated with particular foraminiferal species, such as the family Marinilabiliaceae for Chilostomella ovoidea and the family Hyphomicrobiaceae for Bulimina subornata and Bulimina striata. The presence of bacterial groups that are tightly associated to a certain foraminiferal species implies that there may exist unique, potentially symbiotic relationships between foraminifera and bacteria that have been previously overlooked. Furthermore, the foraminifera contained chloroplast reads originating from different sources, likely reflecting trophic preferences and ecological characteristics of the different species. This study demonstrates the potential of 16S rRNA gene metabarcoding in resolving the microbiome composition and diversity of eukaryotic unicellular organisms, providing unique in situ insights into enigmatic deep-sea ecosystems.

Development of robust models for rapid classification of microplastic polymer types based on near infrared hyperspectral images

Hyperspectral data in the near infrared range were examined for nine common types of plastic particles of 1 mm and 100-500 μm sizes on dry and wet glass fiber filters. Weaker peak intensities were detected for small particles compared to large particles, and the reflectances were weaker at longer wavelengths when the particles were measured on a wet filter. These phenomena are explainable due to the effect of the correlation between the particle size and the absorption of infrared light by water. We constructed robust classification models that are capable of classifying polymer types, regardless of particle size or filter conditions (wet vs. dry), based on hyperspectral data for small particles measured on wet filters. Using the models, we also successfully classified the polymer type of polystyrene beads covered with microalgae, which simulates the natural conditions of microplastics in the ocean. This study suggests that hyperspectral imaging techniques with appropriate classification models allow the identification of microplastics without the time- and labor-consuming procedures of drying samples and removing biofilms, thus enabling more rapid analyses.

Plastic additives in deep-sea debris collected from the western North Pacific and estimation for their environmental loads

Plastic waste has become a growing concern in terms of marine pollution, but little information is available on plastic debris and its possible risks of chemical additives exposure in the deep-sea. This study focused on identification of polymer type and additive concentrations in 21 plastic debris collected from deep-sea of Sagami Bay, Japan and West Pacific Ocean under the Kuroshio Extension and its recirculation gyre (KERG) zone (water depth: 1388-5819 m). Polyethylene (PE) was dominant polymer (57% of the total) in samples, followed by polyvinylchloride (PVC), epoxy resin, polyester (PES), and polypropylene. In plastic additives, bis (2-ethylhexyl) phthalate (DEHP) was detected to be contained in a PVC sheet at concentration of 48%. Butylated hydroxytoluene (BHT) was also detected in PE plastic debris with median concentration of 12,000 ng/g. PES clothes were detected to contain dyeing mixtures, 1,2,4-trichlorobenzene (1,2,4-TCB), up to 42,000 ng/g. Knowing the estimated number of plastic debris under KE current, the minimum burden of chemical additives were estimated that 720 kg of dibutyl phthalate, 570 kg of BHT, 230 kg of DEHP, and 160 kg of 1,2,4-TCB exist on the seabed of KERG zone. This result strongly suggests that enormous amount of hazardous additives lie within plastic debris on abyssal level of the ocean.

Imaging of electrostatic field vector distribution

This paper reports on the visualization of a two-dimensional distribution of electrostatic field vectors around an electrified object using the electric field imager (EFIM) device. The EFIM device is made of a virtually connected pair of plate electrodes in parallel and in proximity, between which an electronic circuit for detection and optical indication is embedded. The EFIM device is not only accurately sensitive to the electrostatic field but also possessed of agility and mobility together with directivity and noninvasiveness. It was successfully demonstrated that electrostatic field vectors were visualized quantitatively, and their spatial distributions were mapped in combination with rather simple, mobile, and low-cost equipment. The advantages and disadvantages of the EFIM visualization scheme are discussed together with the future prospect of the EFIM device.

Massive occurrence of benthic plastic debris at the abyssal seafloor beneath the Kuroshio Extension, the North West Pacific

The abyss (3500-6500 m) covers the bulk of the deep ocean floor yet little is known about the extent of plastic debris on the abyssal seafloor. Using video imagery we undertook a quantitative assessment of the debris present on the abyssal seafloor (5700-5800 m depth) beneath the Kuroshio Extension current system in the Northwest Pacific. This body of water is one of the major transit pathways for the massive amounts of debris that are entering the North Pacific Ocean from Asia. Shallower sites (1400-1500 m depth) were also investigated for comparison. The dominant type of debris was single-use plastics - mainly bags and food packaging. The density of the plastic debris (mean 4561 items/km²) in the abyssal zone was the highest recorded for an abyssal plain suggesting that the deep-sea basin in the Northwest Pacific is a significant reservoir of plastic debris.

Abundant Chitinous Structures in Chilostomella (Foraminifera, Rhizaria) and Their Potential Functions

Benthic foraminifera, members of Rhizaria, inhabit a broad range of marine environments and are particularly common in hypoxic sediments. The biology of benthic foraminifera is key to understanding benthic ecosystems and relevant biogeochemical cycles, especially in hypoxic environments. Chilostomella is a foraminiferal genus commonly found in hypoxic deep-sea sediments and has poorly understood ecological characteristics. For example, the carbon isotopic compositions of their lipids are substantially different from other co-occurring genera, probably reflecting unique features of its metabolism. Here, we investigated the cytoplasmic and ultrastructural features of Chilostomella ovoidea from bathyal sediments of Sagami Bay, Japan, based on serial semi-thin sections examined using an optical microscope followed by a three-dimensional reconstruction, combined with TEM observations of ultra-thin sections. Observations by TEM revealed the presence of abundant electron-dense structures dividing the cytoplasm. Based on histochemical staining, these structures are shown to be composed of chitin. Our 3D reconstruction revealed chitinous structures in the final seven chambers. These exhibited a plate-like morphology in the final chambers but became rolled up in earlier chambers (toward the proloculus). These chitinous, plate-like structures may function to partition the cytoplasm in a chamber to increase the surface/volume ratio and/or act as a reactive site for some metabolic functions.

Characterization of microplastics on filter substrates based on hyperspectral imaging: Laboratory assessments

Microplastic pollution has become an urgent issue because it adversely affects ecosystems. However, efficient methods to detect and characterize microplastic particles are still in development. By conducting a series of laboratory assessments based on near-infrared hyperspectral imaging in the wavelength range of 900-1700 nm, we report the fundamental spectral features of (i) 11 authentic plastics and (ii) 11 filter substrate materials. We found that different plastic polymers showed distinct spectral features at 1150-1250 nm, 1350-1450 nm and 1600-1700 nm, enabling their automatic recognition and identification with spectral separation algorithms. Using an improved hyperspectral imaging system, we demonstrated the detection of three types of microplastic particles, polyethylene, polypropylene and polystyrene, down to 100 μm in diameter. As a filter substrate, a gold-coated polycarbonate filter (GPC0847-BA) showed constant reflectance over 900-1700 nm and a large radiative contrast against loaded plastic particles. Glass fiber filters (GF10 and GF/F) would also be suitable substrates due to their low cost and easy commercial availability. This study provides key parameters for applying hyperspectral imaging techniques for the detection of microplastics.

Sediment sampling with a core sampler equipped with aluminum tubes and an onboard processing protocol to avoid plastic contamination

Microplastics are abundant even on the deep-sea floor far from land and the ocean surface where human activities take place. To obtain samples of microplastics from the deep-sea floor, a research vessel and suitable sampling equipment, such as a multiple corer, a box corer, or a push corer manipulated by a remotely operated (ROV) or human occupied vehicle (HOV) are needed. Most such corers use sampling tubes made of plastic, such as polycarbonate, acrylic, or polyvinyl chloride. These plastic tubes are easily scratched by sediment particles, in particular during collection of coarse sandy sediments, and, consequently, the samples may become contaminated with plastic from the tube. Here, we report on the use of aluminum tubes with both a multiple corer and a push corer to prevent such plastic contamination. When compared with plastic tubes, aluminum tubes have the disadvantages of heavier weight and non-transparency. We suggest ways to overcome these problems, and we also present an onboard processing protocol to prevent plastic contamination during sediment core sampling when plastic tubes are used.

•

Use of a sediment corer with aluminum tubes reduces the risk of plastic contamination in the sediment samples

•

The proposed method allows undisturbed sediment cores to be retrieved with comparable efficiency to conventional transparent core tubes

A statistical model for activation of Factor C by binding to LPS aggregates

Published data on Factor C activity at various LPS and Lipid A concentrations (Nakamura et al. in Eur J Biochem 176:89, 1988; Kobayashi et al. in J Biol Chem 37:25987, 2014) were rearranged to show that Factor C exhibited its maximum activity at a specific concentration of LPS. A statistical model was proposed for examining whether a single LPS molecule binding activates Factor C (monomeric activation) or dimerization of Factor C is necessary for the activation (dimeric activation). In the monomeric activation model the plots of the relative activity of Factor C against the molar ratio of LPS to Factor C were different from those in the published data. The plots in the dimeric activation model lie on a bell-shaped curve, whatever the Factor C concentration, matching the published data and indicating the appropriateness of that model. We suggest that Factor C is activated by multiple molecular interactions of Factor C with LPS aggregates on which it dimerises and that this explains why larger aggregates are less effective at activating Factor C than smaller ones.

A new small device made of glass for separating microplastics from marine and freshwater sediments

Separating microplastics from marine and freshwater sediments is challenging, but necessary to determine their distribution, mass, and ecological impacts in benthic environments. Density separation is commonly used to extract microplastics from sediments by using heavy salt solutions, such as zinc chloride and sodium iodide. However, current devices/apparatus used for density separation, including glass beakers, funnels, upside-down funnel-shaped separators with a shut-off valve, etc., possess various shortcomings in terms of recovery rate, time consumption, and/or usability. In evaluating existing microplastic extraction methods using density separation, we identified the need for a device that allows rapid, simple, and efficient extraction of microplastics from a range of sediment types. We have developed a small glass separator, without a valve, taking a hint from an Utermöhl chamber. This new device is easy to clean and portable, yet enables rapid separation of microplastics from sediments. With this simple device, we recovered 94–98% of <1,000 µm microplastics (polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, and polystyrene). Overall, the device is efficient for various sizes, polymer types, and sediment types. Also, microplastics collected with this glass-made device remain chemically uncontaminated, and can, therefore, be used for further analysis of adsorbing contaminants and additives on/to microplastics.

A new method for acquiring images of meiobenthic images using the FlowCAM

The purpose of this study was to develop a new method for investigating sediment-inhabiting meiobenthos using the Flow Cytometer And Microscope (FlowCAM). Meiobenthos are widely recognized as a useful indicator for assessing the effects of anthropogenic and natural disturbances in both shallow and deep ocean ecosystems. These small benthic invertebrates are traditionally investigated by individually counting and identifying specimens under a microscope, which is labor intensive and time consuming. However, FlowCAM, which was originally developed to semiautomatically analyze microplankton, has the potential to resolve these challenges. Meiobenthic specimens were extracted from sediment using the centrifugal separation method and were then pipetted into the FlowCAM system and imaged. The images were then used to classify and count the specimens at high taxonomic levels to verify the effectiveness of this method compared with traditional methods. We found that FlowCAM system:

•

Enabled sufficient meiobenthic images to be obtained to allow the identification and classification of specimens at high taxonomic levels.

•

Obtained comparable numbers of individuals to traditional methods.

•

Has the potential to rapidly process large the volumes of meiobenthos samples that are required when monitoring seasonal and spatial variation in ocean ecosystems and conducting long-term environmental impact assessments.

Compound-specific isotope analysis of benthic foraminifer amino acids suggests microhabitat variability in rocky-shore environments

The abundance and biomass of benthic foraminifera are high in intertidal rocky-shore habitats. However, the availability of food to support their high biomass has been poorly studied in these habitats compared to those at seafloor covered by sediments. Previous field and laboratory observations have suggested that there is diversity in the food preferences and modes of life among rocky-shore benthic foraminifera. In this study, we used the stable nitrogen isotopic composition of amino acids to estimate the trophic position, trophic niche, and feeding strategy of individual foraminifera species. We also characterized the configuration and structure of the endobiotic microalgae in foraminifera using transmission electron microscopy, and we identified the origin of endobionts based on nucleotide sequences. Our results demonstrated a large variation in the trophic positions of different foraminifera from the same habitat, a reflection of endobiotic features and the different modes of life and food preferences of the foraminifera. Foraminifera did not rely solely on exogenous food sources. Some species effectively used organic matter derived from endobionts in the cell cytoplasm. The high biomass and species density of benthic foraminifera found in intertidal rocky-shore habitats are thus probably maintained by the use of multiple nitrogen resources and by microhabitat segregation among species as a consequence.

Proton pumping accompanies calcification in foraminifera

Ongoing ocean acidification is widely reported to reduce the ability of calcifying marine organisms to produce their shells and skeletons. Whereas increased dissolution due to acidification is a largely inorganic process, strong organismal control over biomineralization influences calcification and hence complicates predicting the response of marine calcifyers. Here we show that calcification is driven by rapid transformation of bicarbonate into carbonate inside the cytoplasm, achieved by active outward proton pumping. Moreover, this proton flux is maintained over a wide range of pCO₂ levels. We furthermore show that a V-type H⁺ ATPase is responsible for the proton flux and thereby calcification. External transformation of bicarbonate into CO₂ due to the proton pumping implies that biomineralization does not rely on availability of carbonate ions, but total dissolved CO₂ may not reduce calcification, thereby potentially maintaining the current global marine carbonate production.

Despite their role in oceanic CaCO₃ production, the physiological processes responsible for calcification in foraminifera are poorly understood Here, the authors show that calcification is driven by rapid transformation of bicarbonate to carbonate inside the cytoplasm, achieved by active outward proton pumping.

Levobupivacaine-dextran mixture for transversus abdominis plane block and rectus sheath block in patients undergoing laparoscopic colectomy: a randomised controlled trial

We performed a randomised controlled double-blinded study of patients having laparoscopic colectomy with bilateral transversus abdominis plane block plus rectus sheath block, comparing a control group receiving 80 ml levobupivacaine 0.2% in saline with a dextran group receiving 80 ml levobupivacaine 0.2% in 8% low-molecular weight dextran. Twenty-seven patients were studied in each group. The mean (SD) maximum plasma concentration of levobupivacaine in the control group (1410 (322) ng.ml(-1) ) was higher than the dextran group (1141 (287) ng.ml(-1) ; p = 0.004), and was reached more quickly (50.6 (30.2) min vs 73.2 (24.6) min; p = 0.006). The area under the plasma concentration-time curve from 0 min to 240 min in the control group (229,124 (87,254) ng.min.ml(-1) ) was larger than in the dextran group (172,484 (50,502) ng.min.ml(-1) ; p = 0.007). The median (IQR [range]) of the summated numerical pain rating score at rest during the first postoperative 24 h in the control group (16 (9-20 [3-31]) was higher than in the dextran group (8 (2-11 [0-18]); p = 0.0001). In this study, adding dextran to levobupivacaine decreased the risk of levobupivacaine toxicity while providing better analgesia.

Intracellular Isotope Localization in Ammonia sp. (Foraminifera) of Oxygen-Depleted Environments: Results of Nitrate and Sulfate Labeling Experiments

Some benthic foraminiferal species are reportedly capable of nitrate storage and denitrification, however, little is known about nitrate incorporation and subsequent utilization of nitrate within their cell. In this study, we investigated where and how much (15)N or (34)S were assimilated into foraminiferal cells or possible endobionts after incubation with isotopically labeled nitrate and sulfate in dysoxic or anoxic conditions. After 2 weeks of incubation, foraminiferal specimens were fixed and prepared for Transmission Electron Microscopy (TEM) and correlative nanometer-scale secondary ion mass spectrometry (NanoSIMS) analyses. TEM observations revealed that there were characteristic ultrastructural features typically near the cell periphery in the youngest two or three chambers of the foraminifera exposed to anoxic conditions. These structures, which are electron dense and ~200-500 nm in diameter and co-occurred with possible endobionts, were labeled with (15)N originated from (15)N-labeled nitrate under anoxia and were labeled with both (15)N and (34)S under dysoxia. The labeling with (15)N was more apparent in specimens from the dysoxic incubation, suggesting higher foraminiferal activity or increased availability of the label during exposure to oxygen depletion than to anoxia. Our results suggest that the electron dense bodies in Ammonia sp. play a significant role in nitrate incorporation and/or subsequent nitrogen assimilation during exposure to dysoxic to anoxic conditions.

Early optimization of antimicrobial therapy improves clinical outcomes of patients administered agents targeting methicillin-resistant Staphylococcus aureus

WHAT IS KNOWN AND OBJECTIVE

Antimicrobial stewardship is required to ensure the appropriate use of antimicrobials. However, no reports have been published on clinical outcomes of implementation of antimicrobial stewardship in patients receiving pathogen-specific antibiotics.

METHOD

To evaluate the clinical outcomes of patients who received drugs, we conducted a single-centre, retrospective study of the effects of an antimicrobial stewardship programme targeting methicillin-resistant Staphylococcus aureus (MRSA).

RESULTS

The time to administer effective antimicrobials was significantly (median number of days, 3 before vs. 0 after, P < 0·001) shortened, and the rate of de-escalation was significantly elevated (47·1% vs. 96·2%, P < 0·001) after implementation of daily review. The 60-day clinical failure associated with Gram-positive bacterial infection was significantly reduced (33·3% vs. 17·6%, P = 0·007) after intervention.

WHAT IS NEW AND CONCLUSIONS

Daily review of administration of antimicrobials targeting MRSA was highly effective in improving clinical outcomes by optimizing early antimicrobial therapy.

Bone marrow lesions, subchondral bone cysts and subchondral bone attrition are associated with histological synovitis in patients with end-stage knee osteoarthritis: a cross-sectional study

OBJECTIVE

The aim of this study was to examine the osteoarthritis (OA)-related structural changes associated with histological synovitis in end-stage knee OA patients.

METHODS

Forty end-stage knee OA patients (female: 88%, mean age: 71.8 y) were enrolled. All participants underwent 3.0-T MRI. The structural changes, such as cartilage morphology, subchondral bone marrow lesion (BML), subchondral bone cyst (SBC), subchondral bone attrition (SBA), osteophytes, meniscal lesion and synovitis, were scored using the whole-organ MRI scoring (WORMS) method. Synovial samples were obtained from five regions of interest (ROIs) of the knee joint during total joint replacement surgery. The associations between the histological synovitis score (HSS) and WORMS or the synovial expression levels of cyclooxygenase (COX)-2, interleukin (IL)-1β, IL-6 and transforming growth factor (TGF)-β were examined using Spearman's correlation coefficient.

RESULTS

Among the seven OA-related structural changes, the BML, SBC, SBA and synovitis were significantly associated with the HSS (r = 0.33, 0.35, 0.48 and 0.36, respectively), while other morphological changes were not. Although synovial COX-2, IL-1β or IL-6 expression levels were not associated with the HSS, the synovial TGF-β expression levels were associated with the HSS.

CONCLUSION

The presence of BML, SBC and SBA was associated with histological synovitis in end-stage knee OA patients.

Wnt3a signaling induces murine dental follicle cells to differentiate into cementoblastic/osteoblastic cells via an osterix-dependent pathway

BACKGROUND AND OBJECTIVE

Dental follicle cells, putative progenitor cells for cementoblasts, osteoblasts and periodontal ligament cells, interplay with Hertwig's epithelial root sheath (HERS) cells during tooth root formation, in which HERS is considered to have an inductive role in initiating cementogenesis by epithelial-mesenchymal interaction. However, the specific mechanisms controlling the cementoblast/osteoblast differentiation of dental follicle cells are not fully understood. Canonical Wnt signaling has been implicated in increased bone formation by controlling mesenchymal stem cell or osteoblastic cell functions. This study examined the possible expression of canonical Wnt ligand in HERS and the role of Wnt signaling during the cementoblast/osteoblast differentiation of dental follicle cells.

MATERIAL AND METHODS

The expression of Wnt3a, a representative canonical Wnt ligand, in HERS was assessed by immunohistochemistry. The differentiation and function of immortalized murine dental follicle cells were evaluated by measuring alkaline phosphatase (ALP, Alpl) activity and osteogenic gene expression.

RESULTS

We identified the expression of Wnt3a in HERS during mouse tooth root development by immunohistochemistry as well as in cultured human epithelial rest cells of Malassez by real-time polymerase chain reaction, while no expression of Wnt3a was detected in cultured dental mesenchymal cells. Exposure of immortalized murine dental follicle cells to Wnt3a-induced ALP activity as well as expression of the Alpl gene. Pretreatment of cells with Dickkopf-1, a potent canonical Wnt antagonist, markedly attenuated the effect of Wnt3a on ALP expression. Furthermore, Wnt3a induced transcriptional activity of runt-related transcription factor 2 (Runx2) and expression of osterix at gene and/or protein levels. Treatment with osterix-small interfering RNA significantly inhibited Wnt3a-induced ALP expression at gene and protein levels.

CONCLUSION

These findings suggest that HERS has a potential role in stimulating cementoblast/osteoblast differentiation of dental follicle cells via the Wnt/β-catenin signaling pathway.

Expression of umami-taste-related genes in the tongue: a pilot study for genetic taste diagnosis

OBJECTIVE

Expression of taste-related genes in the tongue was analysed to develop a technique for genetic diagnosis of umami taste disorders.

MATERIALS AND METHODS

Tissue samples were collected from healthy volunteers by scraping the foliate papillae of the tongue. Immunocytochemistry staining of gustducin, a taste-cell-specific G protein, and gene expression analysis by real-time polymerase chain reaction of β-actin, gustducin (GNAT3) and umami receptors (T1R1, T1R3 and mGluR1) were performed. Changes in umami receptor expression following application of umami substances onto the tongue were analysed.

RESULTS

Gustducin-positive cells were observed in the samples, indicating the presence of taste cells. Gene expression of β-actin, GNAT3, T1R1 and T1R3 was detected in all seven samples tested, while that of mGluR1 was detected in four samples. Sequence analysis by NCBI Blast showed that each polymerase chain reaction product had a 99% rate of identification of its target sequence. Stimulation of the tongue with monosodium glutamate significantly upregulated the gene expression levels of T1R1 and T1R3, indicating that this method can detect alterations in umami-related gene expression.

CONCLUSION

Evaluation of the expression of the umami receptor genes, T1R1 and T1R3, in the tongue may be clinically useful for objective genetic diagnosis of umami taste disorders.

Cytologic and Genetic Characteristics of Endobiotic Bacteria and Kleptoplasts of Virgulinella fragilis (Foraminifera)

The benthic foraminifer Virgulinella fragilis Grindell and Collen 1976 has multiple putative symbioses with both bacterial and kleptoplast endobionts, possibly aiding its survival in environments from dysoxia (5-45 μmol-O2 /L) to microxia (0-5 μmol-O2 /L) and in the dark. To clarify the origin and function of V. fragilis endobionts, we used genetic analyses and transmission electron microscope observations. Virgulinella fragilis retained δ-proteobacteria concentrated at its cell periphery just beneath the cell membranes. Unlike another foraminifer Stainforthia spp., which retains many bacterial species, V. fragilis has a less variable bacterial community. This suggests that V. fragilis maintains a specific intracellular bacterial flora. Unlike the endobiotic bacteria, V. fragilis klepto-plasts originated from various diatom species and are found in the interior cytoplasm. We found evidence of both retention and digestion of kleptoplasts, and of fragmentation of the kleptoplastid outer membrane that likely facilitates transport of kleptoplastid products to the host. Accumulations of mitochondria were observed encircling endobiotic bacteria. It is likely that the bacteria use host organic material for carbon oxidation. The mitochondria may use oxygen available around the δ-proteobacteria and synthesize adenosine triphosphate, perhaps for sulfide oxidation.

Preoperative hydroperoxide concentrations are associated with a risk of postoperative complications after cardiac surgery

This study aimed to assess whether preoperative oxidative stress levels can predict postoperative complications in patients undergoing cardiac surgery. Ninety-five cardiac surgery patients received an assessment of preoperative oxidative stress by measurement of hydroperoxide values in blood via the d-Rom test. Area under the receiver operating characteristic curve and also multivariate logistic regression were used to evaluate the prognostic significance of preoperative hydroperoxide concentrations in predicting the occurrence of major organ morbidity and mortality (MOMM). MOMM included death, deep sternal infection, reoperation, stroke, renal failure requiring haemodialysis and prolonged ventilation (>48 hours). The ability of preoperative hydroperoxide concentrations to predict MOMM was not significantly different from that of the European system for cardiac operative risk evaluation (EuroSCORE) (area under the receiver operating characteristic curve 0.822 versus 0.821 respectively, P=0.983). The optimal threshold value of hydroperoxide concentration to differentiate between patients with and without MOMM was 450 UCarr (sensitivity, 87.0%; specificity, 81.9%). Duration of intensive care unit stay, mechanical ventilation time and hospital stay were significantly longer in patients with preoperative hydroperoxide concentrations ≥450 UCarr (H group) compared to those patients with preoperative hydroperoxide concentrations <450 UCarr (L group). An increase in preoperative hydroperoxide concentrations remained associated with an increased risk of MOMM (odds ratios: 1.01, 95% confidence interval: 1.00 to 1.03) and prolonged intensive care unit stay (odds ratio 1.01, 95% confidence interval: 1.00 to 1.02), after adjusting for age, gender and EuroSCORE. In conclusion, an increased hydroperoxide concentration before cardiac surgery is an independent risk factor for severe postoperative complications.

High-resolution food webs based on nitrogen isotopic composition of amino acids

Food webs are known to have myriad trophic links between resource and consumer species. While herbivores have well-understood trophic tendencies, the difficulties associated with characterizing the trophic positions of higher-order consumers have remained a major problem in food web ecology. To better understand trophic linkages in food webs, analysis of the stable nitrogen isotopic composition of amino acids has been introduced as a potential means of providing accurate trophic position estimates. In the present study, we employ this method to estimate the trophic positions of 200 free-roaming organisms, representing 39 species in coastal marine (a stony shore) and 38 species in terrestrial (a fruit farm) environments. Based on the trophic positions from the isotopic composition of amino acids, we are able to resolve the trophic structure of these complex food webs. Our approach reveals a high degree of trophic omnivory (i.e., noninteger trophic positions) among carnivorous species such as marine fish and terrestrial hornets.This information not only clarifies the trophic tendencies of species within their respective communities, but also suggests that trophic omnivory may be common in these webs.

Ultrasound-guided single shot caudal block anesthesia reduces postoperative urinary catheter-induced discomfort

BACKGROUND

Urinary catheter-induced discomfort during the postoperative period can be distressing, and sometimes results in severe restlessness and agitation, especially in middle-aged and elderly male patients. Recent advances in ultrasound technology have increased the consistency, safety, and ease of a caudal block even in older patients. We speculated that an ultrasound-guided caudal block would be reliable and safe as treatment for such postoperative discomfort.

METHODS

Adult male patients (ASA I-II) undergoing cervical laminoplasty were allocated to either the caudal block (CB, N.=24) or non-block (NB, N.=24) group. Following anesthesia induction, urinary catheterization was performed using a 16 French Foley catheter. Thereafter, an ultrasound-guided caudal block was performed with 8 ml of 0.3% ropivacaine and 100 µg of fentanyl for patients in group CB, while group NB did not receive a caudal block. We assessed urinary catheter-induced discomfort as mild, moderate, or severe at 0, 2, 6, 10, and 18 hours after surgery, and compared the incidence and severity of discomfort between the groups using a randomized double-blind design.

RESULTS

All caudal blocks were successfully performed with 1 or 2 needle insertions. The incidence of urinary catheter-induced discomfort was significantly reduced in group CB as compared to NB at 0, 2, and 6 hours, while severity was also reduced at 0 and 2 hours. No patient required re-catheterization due to urinary retention after catheter removal. There were no other complications related to the caudal block.

CONCLUSION

Preoperative ultrasound-guided single shot caudal block anesthesia safely reduced postoperative urinary catheter-induced discomfort in our male patients.

The factors associated with pain severity in patients with knee osteoarthritis vary according to the radiographic disease severity: a cross-sectional study

OBJECTIVES

Knee osteoarthritis (OA) pain is suggested to be associated with inflammation and detrimental mechanical loading across the joint. In this cross-sectional study, we simultaneously examined the inflammation and alignment of the lower limb and examined how the pain components varied depending on the disease progression.

DESIGN

One-hundred sixty female medial type of early- [n = 74 in Kellgren-Lawrence (K/L) 2] to advanced-stage (n = 96 in K/L >2) knee OA subjects (70.5 years on average) were enrolled. Knee pain was evaluated using a pain visual analog scale (VAS) and the pain-related subcategory of the Japanese Knee Osteoarthritis Measure (JKOM-pain). The serum interleukin (sIL)-6 level reflecting synovitis, and the high sensitivity C-reactive protein (hs-CRP) level were measured to evaluate the severity of inflammation. The anatomical axis angle (AAA) was measured as an alignment index. The β-coefficient was estimated after adjusting for age and the body mass index (BMI) using a multiple linear regression analysis.

RESULTS

Multiple linear regression analyses showed that the sIL-6 levels, but not AAA, associated with the pain VAS [β = 10.77 (95% confidence interval (CI): 4.14-17.40), P < 0.01] and JKOM-pain scores [β = 3.19 (95% CI: 1.93-4.44), P < 0.001] in the early stage. Conversely, AAA, but not the sIL-6 levels, was found to be associated with the pain VAS [β = -1.29 (95% CI: -2.51 to -0.08), P < 0.05] and JKOM-pain scores [β = -0.49 (95% CI: -0.82 to -0.16), P < 0.01] in the advanced stage.

CONCLUSIONS

The presence of a higher level of sIL-6 and the varus alignment of the joint is associated with pain in early- and advanced-stage knee OA patients, respectively.

Transversus abdominis plane block in combination with general anesthesia provides better intraoperative hemodynamic control and quicker recovery than general anesthesia alone in high-risk abdominal surgery patients

BACKGROUND

Patients with severe cardiovascular disease are frequently hemodynamically unstable during abdominal surgery. Improving the safety of such patients by stabilizing intraoperative hemodynamics remains a major concern for anesthesiologists. Transversus abdominis plane (TAP) block in combination with general anesthesia may facilitate optimum anesthetic management of these high-risk patients.

METHODS

Patients with cardiovascular disease classified as American Society of Anesthesiologists (ASA) physical status 3 were enrolled. The patients were undergoing elective abdominal surgery and were randomized to a group receiving general anesthesia and TAP block (Group T, N.=33) or a group receiving general anesthesia alone (Group G, N.=35). We compared the groups for intraoperative hemodynamic stability, anesthesia emergence time, amounts of anesthetics and opioids given, and frequency of emergency treatment with cardiovascular agents. A preliminary study demonstrated that systolic blood pressure and heart rate were maintained stable within 70-110% of their preanesthesia values throughout surgery in ASA 1 elderly patients without cardiovascular disease. Thus, the hemodynamically stable time was defined as the time when systolic blood pressure and heart rate were 70-110% of their preanesthesia values. The ratio of hemodynamically stable time to total operative time was used as an index of hemodynamic stability.

RESULTS

The median (minimum-maximum) percentage of hemodynamically stable time was longer in Group T (91[50-100]%) than Group G (79[40-91]%, P<0.01). The mean sevoflurane concentration, amount of fentanyl given and frequency of vasopressor use were lower in Group T than Group G (P<0.05). Anesthesia emergence time was shorter in Group T (14[4-30] min) than Group G (18[9-52] min, P<0.01). No worsening of cardiovascular complications was observed.

CONCLUSION

For abdominal surgery in patients with severe cardiovascular disease, combining TAP block with general anesthesia promotes intraoperative hemodynamic stability and early emergence from anesthesia.

Algivore or phototroph? Plakobranchus ocellatus (Gastropoda) continuously acquires kleptoplasts and nutrition from multiple algal species in nature

The sea slug Plakobranchus ocellatus (Sacoglossa, Gastropoda) retains photosynthetically active chloroplasts from ingested algae (functional kleptoplasts) in the epithelial cells of its digestive gland for up to 10 months. While its feeding behavior has not been observed in natural habitats, two hypotheses have been proposed: 1) adult P. ocellatus uses kleptoplasts to obtain photosynthates and nutritionally behaves as a photoautotroph without replenishing the kleptoplasts; or 2) it behaves as a mixotroph (photoautotroph and herbivorous consumer) and replenishes kleptoplasts continually or periodically. To address the question of which hypothesis is more likely, we examined the source algae for kleptoplasts and temporal changes in kleptoplast composition and nutritional contribution. By characterizing the temporal diversity of P. ocellatus kleptoplasts using rbcL sequences, we found that P. ocellatus harvests kleptoplasts from at least 8 different siphonous green algal species, that kleptoplasts from more than one species are present in each individual sea slug, and that the kleptoplast composition differs temporally. These results suggest that wild P. ocellatus often feed on multiple species of siphonous algae from which they continually obtain fresh chloroplasts. By estimating the trophic position of wild and starved P. ocellatus using the stable nitrogen isotopic composition of amino acids, we showed that despite the abundance of kleptoplasts, their photosynthates do not contribute greatly to the nutrition of wild P. ocellatus, but that kleptoplast photosynthates form a significant source of nutrition for starved sea slugs. The herbivorous nature of wild P. ocellatus is consistent with insights from molecular analyses indicating that kleptoplasts are frequently replenished from ingested algae, leading to the conclusion that natural populations of P. ocellatus do not rely on photosynthesis but mainly on the digestion of ingested algae.

Is the 7/2(1)- isomer state of 43S spherical?

We report on the spectroscopic quadrupole moment measurement of the 7/2(1)(-) isomeric state in (16)(43)S(27) [E*=320.5(5) keV, T(1/2)=415(3) ns], using the time dependent perturbed angular distribution technique at the RIKEN RIBF facility. Our value, |Q(s)|=23(3) efm(2), is larger than that expected for a single-particle state. Shell model calculations using the modern SDPF-U interaction for this mass region reproduce remarkably well the measured |Q(s)|, and show that non-negligible correlations drive the isomeric state away from a purely spherical shape.