Ultrahigh foraging rates of Baikal seals make tiny endemic amphipods profitable in Lake Baikal.

Understanding what, how, and how often apex predators hunt is important due to their disproportionately large effects on ecosystems. In Lake Baikal with rich endemic fauna, Baikal seals appear to eat, in addition to fishes, a tiny (<0.1 g) endemic amphipod Macrohectopus branickii (the world's only freshwater planktonic species). Yet, its importance as prey to seals is unclear. Globally, amphipods are rarely targeted by single-prey feeding (i.e., nonfilter-feeding) mammals, presumably due to their small size. If M. branickii is energetically important prey, Baikal seals would exhibit exceptionally high foraging rates, potentially with behavioral and morphological specializations. Here, we used animal-borne accelerometers and video cameras to record Baikal seal foraging behavior. Unlike the prevailing view that they predominantly eat fishes, they also hunted M. branickii at the highest rates (mean, 57 individuals per dive) ever recorded for single-prey feeding aquatic mammals, leading to thousands of catches per day. These rates were achieved by gradual changes in dive depth following the diel vertical migration of M. branickii swarms. Examining museum specimens revealed that Baikal seals have the most specialized comb-like postcanine teeth in the subfamily Phocinae, allowing them to expel water while retaining prey during high-speed foraging. Our findings show unique mammal-amphipod interactions in an ancient lake, demonstrating that organisms even smaller than krill can be important prey for single-prey feeding aquatic mammals if the environment and predators' adaptations allow high foraging rates. Further, our finding that Baikal seals directly eat macroplankton may explain why they are so abundant in this ultraoligotrophic lake.

A Strategic Protocol to Improve the Process and Outcomes of Two-stage Revision Total Hip Arthroplasty.

Two-stage revision total hip arthroplasty (THA) is the most commonly used treatment approach for deep prosthetic infection. However, in this approach the interval between the first and second stage tends to be prolonged. We devised a strategic protocol for improving the infection eradication rate and shortening the interval between the stages in two-stage revision THA. This study analyzed a series of 14 patients (14 hips) from 2008 to 2012, who were treated using an antibiotic-loaded acrylic cement (ALAC) spacer at the first stage and re-implantation at the second stage. The ALAC included vancomycin and amikacin for most of the cases. Patients with MRSA infection were additionally administered intravenous vancomycin in combination with either oral rifampicin or trimethoprim-sulfamethoxazole. The average interval between the stages was 54.2 days overall, and 58.7 days for cases with MRSA infection. Our infection eradication rate was 100%, with no reported recurrence of infection. The presence of MRSA tended to be associated with a longer interval between the two stages. Our protocol for two-stage revision THA was associated with a high eradication rate of infection and a shortened interval between the stages.

Blue Light Perception by Both Roots and Rhizobia Inhibits Nodule Formation in Lotus japonicus.

In many legumes, roots that are exposed to light do not form nodules. Here, we report that blue light inhibits nodulation in Lotus japonicus roots inoculated with Mesorhizobium loti. Using RNA interference, we suppressed the expression of the phototropin and cryptochrome genes in L. japonicus hairy roots. Under blue light, plants transformed with an empty vector did not develop nodules, whereas plants exhibiting suppressed expression of cry1 and cry2 genes formed nodules. We also measured rhizobial growth to investigate whether the inhibition of nodulation could be caused by a reduced population of rhizobia in response to light. Although red light had no effect on rhizobial growth, blue light had a strong inhibitory effect. Rhizobial growth under blue light was partially restored in signature-tagged mutagenesis (STM) strains in which LOV-HK/PAS- and photolyase-related genes were disrupted. Moreover, when Ljcry1A and Ljcry2B-silenced plants were inoculated with the STM strains, nodulation was additively increased. Our data show that blue light receptors in both the host plant and the symbiont have a profound effect on nodule development. The exact mechanism by which these photomorphogenetic responses function in the symbiosis needs further study, but they are clearly involved in optimizing legume nodulation.

Drift dives and prolonged surfacing periods in Baikal seals: resting strategies in open waters?

Many pinnipeds frequently rest on land or ice, but some species remain in open waters for weeks or months, raising the question of how they rest. A unique type of dive, called drift dives, has been reported for several pinnipeds with suggested functions of rest, food processing and predator avoidance. Prolonged surfacing periods have also been observed in captive seals and are thought to aid food processing. However, information from other species in a different environment would be required to better understand the nature and function of this behavior. In this study, we attached multi-sensor tags to Baikal seals Pusa sibirica, a rare, freshwater species that has no aquatic predators and few resting grounds during the ice-free season. The seals exhibited repeated drift dives (mean depth, 116 m; duration, 10.1 min) in the daytime and prolonged periods at the surface (mean duration, 1.3 h) mainly around dawn. Drift dives and prolonged surfacing periods were temporally associated and observed between a series of foraging dives, suggesting a similar function, i.e. a combination of resting and food processing. The maximum durations of both drift and foraging dives were 15.4 min, close to the aerobic dive limit of this species; therefore, metabolic rates might not be significantly depressed during drift dives, further supporting the function of food processing rather than purely resting. Our results also show that drift diving can occur in a predator-free environment, and thus predator avoidance is not a general explanation of drift dives in pinnipeds.

In vivo wear particles of remelted highly crosslinked polyethylene after total hip arthroplasty: report of four cases.

This is the first report of in vivo wear particles from four total hip arthroplasties using remelted highly crosslinked polyethylene. The number of particles was (1.51 ± 0.45) × 10(7) g(-1) (mean ± standard error); particle size (equivalent circle diameter), 0.72 ± 0.15 µm; and roundness, 1.45 ± 0.05. Remelted highly crosslinked polyethylene generates fewer, rounder, equivalently sized particles compared with corresponding reported values for particles generated from conventional polyethylene.

Development and evaluation of a video exercise program for locomotive syndrome in the elderly.

OBJECTIVES: To develop and evaluate an exercise program that the elderly could sustainably perform in the community or at home to recover from locomotive syndrome. METHODS: We produced 2 types of teaching media, video and pamphlet, describing 10 physical and mobility training exercises. The pilot study examined changes in pulse rate, percutaneous oxygen saturation (SpO2), and the Borg scale rating of perceived exertion in 20 elderly volunteers. Separately, 120 elderly subjects were recruited and divided into 3 groups according to the teaching medium (video, group V; pamphlet, group P; none, group C). Before and 3 months after the intervention, visual analog scale (VAS) scores of low back and knee pain, single-leg standing time, 6-m walking time, Roland-Morris Disability Questionnaire, Oswestry Disability Index, Short Form-8, and 25-question Geriatric Locomotive Function Scale were evaluated. RESULTS: Pulse-rate changes before and after exercise did not exceed 20 %, and SpO2 changes were within 4 points in all cases. The Borg scale ranged between 11 and 14. The intergroup comparison revealed the advantage of the video program in improving the VAS of low back pain, left-leg standing time, and 6-m walking time. CONCLUSION: A video exercise program can potentially aid recovery from locomotive syndrome in the elderly.

Development and evaluation of a video exercise program for locomotive syndrome in the elderly.

OBJECTIVES: To develop and evaluate an exercise program that the elderly could sustainably perform in the community or at home to recover from locomotive syndrome. METHODS: We produced 2 types of teaching media, video and pamphlet, describing 10 physical and mobility training exercises. The pilot study examined changes in pulse rate, percutaneous oxygen saturation (SpO2), and the Borg scale rating of perceived exertion in 20 elderly volunteers. Separately, 120 elderly subjects were recruited and divided into 3 groups according to the teaching medium (video, group V; pamphlet, group P; none, group C). Before and 3 months after the intervention, visual analog scale (VAS) scores of low back and knee pain, single-leg standing time, 6-m walking time, Roland-Morris Disability Questionnaire, Oswestry Disability Index, Short Form-8, and 25-question Geriatric Locomotive Function Scale were evaluated. RESULTS: Pulse-rate changes before and after exercise did not exceed 20 %, and SpO2 changes were within 4 points in all cases. The Borg scale ranged between 11 and 14. The intergroup comparison revealed the advantage of the video program in improving the VAS of low back pain, left-leg standing time, and 6-m walking time. CONCLUSION: A video exercise program can potentially aid recovery from locomotive syndrome in the elderly.

Distinct degree of radiculopathy at different levels of peripheral nerve injury.

BACKGROUND: Lumbar radiculopathy is a common clinical problem, characterized by dorsal root ganglion (DRG) injury and neural hyperactivity causing intense pain. However, the mechanisms involved in DRG injury have not been fully elucidated. Furthermore, little is known about the degree of radiculopathy at the various levels of nerve injury. The purpose of this study is to compare the degree of radiculopathy injury at the DRG and radiculopathy injury proximal or distal to the DRG. RESULTS: The lumbar radiculopathy rat model was created by ligating the L5 nerve root 2 mm proximal to the DRG or 2 mm distal to the DRG with 6.0 silk. We examined the degree of the radiculopathy using different points of mechanical sensitivity, immunohistochemistry and in vivo patch-clamp recordings, 7 days after surgery. The rats injured distal to the DRG were more sensitive than those rats injured proximal to the DRG in the behavioral study. The number of activated microglia in laminas I-II of the L5 segmental level was significantly increased in rats injured distal to the DRG when compared with rats injured proximal to the DRG. The amplitudes and frequencies of EPSC in the rats injured distal to the DRG were higher than those injured proximal to the DRG. The results indicated that there is a different degree of radiculopathy at the distal level of nerve injury. CONCLUSIONS: Our study examined the degree of radiculopathy at different levels of nerve injury. Severe radiculopathy occurred in rats injured distal to the DRG when compared with rats injured proximal to the DRG. This finding helps to correctly diagnose a radiculopathy.

Distribution of antifouling biocides and perfluoroalkyl compounds in sediments from selected locations in Indonesian coastal waters.

Coastal marine environments are considered to be the most sensitive areas for the accumulation of organotin (OT) compounds and other emerging new pollutants, such as perfluoroalkyl compounds. Contamination by these compounds is a matter of great concern due to their accumulation and possible negative impact on the coastal environment and organisms. The concentrations of tributyltin (TBT) compounds were greater in Indonesia, i.e., on the order of Bitung > Manado > Jakarta Bay > Gangga Island, and TBT in sediment from Bitung and Manado was the dominant species among butyltin (BT) compounds. Sea Nine 211, diuron, and irgarol 1051 were detected among alternative biocides in Bitung, Manado, and Gangga Island and irgarol 1051 was detected in Jakarta Bay. Perfluorooctanoic acid (PFOA) and perfluorosulfonic acid (PFOS) in Jakarta Bay were detected at 0.25 to 6.1 µg kg(-1) dry weight (dw) and 0.58 to 3.7 µg kg(-1) dw, respectively, and the concentrations of PFOS at most sampling sites were greater than those of PFOA. Thus, coastal waters from Indonesia have already been contaminated by antifouling biocides and perfluoroalkyl compounds.

Underwater and surface behavior of homing juvenile northern elephant seals.

Northern elephant seals, Mirounga angustirostris, travel between colonies along the west coast of North America and foraging areas in the North Pacific. They also have the ability to return to their home colony after being experimentally translocated. However, the mechanisms of this navigation are not known. Visual information could serve an important role in navigation, either primary or supplementary. We examined the role of visual cues in elephant seal navigation by translocating three seals and recording their heading direction continuously using GPS, and acceleration and geomagnetic data loggers while they returned to the colony. The seals first reached the coast and then proceeded to the colony by swimming along the coast. While underwater the animals exhibited a horizontally straight course (mean net-to-gross displacement ratio=0.94±0.02). In contrast, while at the surface they changed their headings up to 360 deg. These results are consistent with the use of visual cues for navigation to the colony. The seals may visually orient by using landmarks as they swim along the coast. We further assessed whether the seals could maintain a consistent heading while underwater during drift dives where one might expect that passive spiraling during drift dives could cause disorientation. However, seals were able to maintain the initial course heading even while underwater during drift dives where there was spiral motion (to within 20 deg). This behavior may imply the use of non-visual cues such as acoustic signals or magnetic fields for underwater orientation.

Northern elephant seals adjust gliding and stroking patterns with changes in buoyancy: validation of at-sea metrics of body density.

Many diving animals undergo substantial changes in their body density that are the result of changes in lipid content over their annual fasting cycle. Because the size of the lipid stores reflects an integration of foraging effort (energy expenditure) and foraging success (energy assimilation), measuring body density is a good way to track net resource acquisition of free-ranging animals while at sea. Here, we experimentally altered the body density and mass of three free-ranging elephant seals by remotely detaching weights and floats while monitoring their swimming speed, depth and three-axis acceleration with a high-resolution data logger. Cross-validation of three methods for estimating body density from hydrodynamic gliding performance of freely diving animals showed strong positive correlation with body density estimates obtained from isotope dilution body composition analysis over density ranges of 1015 to 1060 kg m(-3). All three hydrodynamic models were within 1% of, but slightly greater than, body density measurements determined by isotope dilution, and therefore have the potential to track changes in body condition of a wide range of freely diving animals. Gliding during ascent and descent clearly increased and stroke rate decreased when buoyancy manipulations aided the direction of vertical transit, but ascent and descent speed were largely unchanged. The seals adjusted stroking intensity to maintain swim speed within a narrow range, despite changes in buoyancy. During active swimming, all three seals increased the amplitude of lateral body accelerations and two of the seals altered stroke frequency in response to the need to produce thrust required to overcome combined drag and buoyancy forces.

Scaling of swim speed in breath-hold divers.

1. Breath-hold divers are widely assumed to descend and ascend at the speed that minimizes energy expenditure per distance travelled (the cost of transport (COT)) to maximize foraging duration at depth. However, measuring COT with captive animals is difficult, and empirical support for this hypothesis is sparse. 2. We examined the scaling relationship of swim speed in free-ranging diving birds, mammals and turtles (37 species; mass range, 0·5-90,000 kg) with phylogenetically informed statistical methods and derived the theoretical prediction for the allometric exponent under the COT hypothesis by constructing a biomechanical model. 3. Swim speed significantly increased with mass, despite considerable variations around the scaling line. The allometric exponent (0·09) was statistically consistent with the theoretical prediction (0·05) of the COT hypothesis. 4. Our finding suggests a previously unrecognized advantage of size in divers: larger animals swim faster and thus could travel longer distance, search larger volume of water for prey and exploit a greater range of depths during a given dive duration. 5. Furthermore, as predicted from the model, endotherms (birds and mammals) swam faster than ectotherms (turtles) for their size, suggesting that metabolic power production limits swim speed. Among endotherms, birds swam faster than mammals, which cannot be explained by the model. Reynolds numbers of small birds (<2 kg) were close to the lower limit of turbulent flow (∼ 3 × 10(5) ), and they swam fast possibly to avoid the increased drag associated with flow transition.

An assessment of selected trace elements in intertidal surface sediments collected from the Peninsular Malaysia.

Concentrations of 11 trace elements (V, Cr, Co, Ni, Cu, Zn, As, Ag, Cd, Pb, and U) were determined in the intertidal surface sediments of Peninsular Malaysia. The average trace element concentrations are ranked as follows: Zn>V>As>Cr>Pb>Cu>Ni>Co>U>g>Cd. Interim Sediment Quality Guidelines (ISQGs) employed in present study are the Australia and New Zealand joint guideline (ANZECC/ARMCANZ), and the Hong Kong authorities. From the pooled data, none of these trace elements have the average concentration above the ISQG-high values. However, As and Ag average concentrations were over the ISQG-low values. Some elements were found to have the average concentration above the ISQG-high and/or ISQG-low in certain locations, including Kampung Pasir Putih (JPP), Lumut Port (ALP), Kuala Perai (PKP), Port Dickson (NPD), and others. The lowest and highest concentrations in a specific sampling location and maritime area varied among the elements, variations that were greatly affected by natural and anthropogenic activities in a given area. For each trace element, there were various levels of concentration among the sampling locations and maritime areas. These patterns indicated pollutant sources of an element for each area perhaps derived from nearby areas and did not widely distributed to other locations. It is necessary for Malaysia to develop an ISQG for effective quick screening and evaluation of the coastal environment of Peninsular Malaysia.

Johor strait as a hotspot for trace elements contamination in peninsular Malaysia.

Present study was conducted to evaluate current status of trace elements contamination in the surface sediments of the Johor Strait. Iron (2.54 +/- 1.24%) was found as the highest occurring element, followed by those of zinc (210.45 +/- 115.4 microg/g), copper (57.84 +/- 45.54 microg/g), chromium (55.50 +/- 31.24 microg/g), lead (52.52 +/- 28.41 microg/g), vanadium (47.76 +/- 25.76 microg/g), arsenic (27.30 +/- 17.11 microg/g), nickel (18.31 +/- 11.77 microg/g), cobalt (5.13 +/- 3.12 microg/g), uranium (4.72 +/- 2.52 microg/g), and cadmium (0.30 +/- 0.30 microg/g), respectively. Bioavailability of cobalt, nickel, copper, zinc, arsenic and cadmium were higher than 50% of total concentration. Vanadium, copper, zinc, arsenic and cadmium were found significantly different between the eastern and western part of the strait (p < 0.05). Combining with other factors, Johor Strait is suitable as a hotspot for trace elements contamination related studies.

Serologic survey of Brucella infection in cetaceans inhabiting along the coast of Japan.

A serologic investigation of Brucella infection was performed in 7 species of cetaceans inhabiting along the coast of Japan. A total of 32 serum samples were examined by enzyme-linked immunosorbent assay (ELISA) using Brucella abortus and B. canis antigens. One serum sample from five melon-headed whales (Peponocephala electra) was positive for B. abortus. No serum sample showed positive for B. canis. The ELISA-positive melon-headed whale serum demonstrated a strong band appearance only against B. abortus antigens in Western blot analysis. Many detected bands were discrete, while some of them had a smeared appearance. The present results indicate that Brucella infection occurred in melon-headed whale population and the bacterial antigenicity is more similar to that of B. abortus than B. canis.

Occurrence of antifouling biocides and fluorinated alkyl compounds in sediment core from deep sea: Suruga Bay, Tosa Bay, and Nankai tough, Japan.

Contamination profiles of antifouling biocides were investigated in a deep-sea environment in Suruga Bay Japan. Significant differences in the tributyltin (TBT) and triphenyltin (TPT) concentrations in subsurface sediment between 850 and 800 m of water depth were not observed (p < 0.05). Organotin (OT) concentrations in sediment core of 0-30.5 cm from a water depth of 800 m were investigated. The butyltins (BTs) and phenyltins (PTs) concentrations were constant between 0 and 15 cm, and, subsequently, the concentration of these compounds increased. The peaks of the BTs and PTs concentrations were observed between 18 and 19 cm. The concentrations of Irgarol 1051 decreased until a core depth of 9 cm, and, the values then became near the detection limit under the 10 cm of core depth. Perfluorooctane sulfonate (PFOS) and perfluorooctanic acid (PFOA) were detected in the sediment core (0-30.5 cm) of Suruga Bay. The concentration of PFOS was high in the 0-5-cm core depth and then decreased. The concentrations of PFOA, however, were at the values near the detection limit throughout the sediment core. The BTs and PTs concentrations in surface sediment from Tosa Bay decreased with water depth. Although Irgarol 1051 was the only alternative compound detected, the value was near the detection limit. PFOS and PFOA were detected in sediment core from Tosa Bay. The concentrations of PFOS became low as the water depth became deeper. TBT, TPT, Sea Nine 211, Diuron and Irgarol 1051 were detected in sediment core (core depth: 10 cm) from the Nankai trough (water depth: 4010 m).

Contamination profiles of antifouling biocides in selected coastal regions of Malaysia.

The concentrations of butyltins (BTs) in sediment from Peninsular Malaysia along the Strait of Malacca and their spatial distribution are discussed. The concentrations of BTs were high in the southern part of Peninsular Malaysia where there is a lot of ship traffic, because trade is prosperous. The concentrations of monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) in sediment from the coastal waters of Peninsular Malaysia were in the range 4.1-242 microg/kg dry weight (dw), 1.1-186 microg/kg dw, and 0.7-228 microg/kg dw, respectively. A higher percentage of TBT was observed in the area where TBT concentrations were high. The concentrations of monophenyltin (MPT), diphenyltin (DPT), and triphenyltin (TPT) were in the range <0.1-121 microg/kg dw, 0.4-27 microg/kg dw, and 0.1-34 microg/kg dw in sediment from Peninsular Malaysia, respectively. MPT was the dominant phenyltin species. MBT, DBT, and TBT in green mussel (Perna viridis) samples were detected in the range 41-102 microg/kg, 3-5 microg/kg, and 8-32 microg/kg, respectively. A tolerable average residue level (TARL) was estimated at 20.4 microg/kg from a tolerable daily intake (TDI) of 0.25 microg TBTO/kg body weight/day. The maximum value of TBT detected in green mussel samples was the value near the TARL. TPTs were not detected in green mussel samples. The concentrations of Diuron and Irgarol 1051 in sediment from Peninsular Malaysia were in the range <0.1-5 microg/kg dw and <0.1-14 microg/kg dw, respectively. High concentrations of these compounds were observed in locations where the concentrations of TBT were high. Sea Nine 211, Dichlofluanid, and Pyrithiones were not detected in sediment. The concentrations of antifouling biocides in Melaka and the Strait of Johor were investigated in detail. BTs were found in similar concentrations among all sampling sites from Melaka, indicating that BT contamination spread off the coast. However, Sea Nine 211, Diuron, and Irgarol 1051 in the sediment from Melaka were high at the mouth of the river. BT concentrations at the Strait of Johor were higher than those in Peninsular Malaysia and Melaka and were high at the narrowest locations with poor flushing of water. The concentrations of antifouling biocides were compared among Malaysia, Thailand, and Vietnam. A higher concentration and wide variations of TBT and TPT in sediment from Malaysia were observed among these countries. The Irgarol 1051 concentrations in sediment from Malaysia were higher than those in Thailand and Vietnam.

Organohalogen contaminants in striped dolphins (Stenella coeruleoalba) from Japan: present contamination status, body distribution and temporal trends (1978-2003).

Organohalogen contaminants including PCBs, DDTs, CHLs, HCHs, HCB, PBDEs and HBCDs were determined in striped dolphins (Stenella coeruleoalba) found stranded at Gogo-shima (n=6, 2003) and collected from Taiji (n=15, 1978-1992) in Japan. All target compounds were significantly detected in all the specimens, indicating ubiquitous contamination of oceanic cetaceans in northwest Pacific Ocean. Examination of body distribution of organohalogens in the six specimens from Gogo-shima showed no significant difference in concentrations among the analyzed tissues, except for brain, which had lower levels possibly due to the existence of blood-brain barrier. For evaluating temporal trends, archived blubber samples of adult male stripped dolphins collected in 1978, 1979, 1986 and 1992 were analyzed. Concentrations of PCBs, DDTs and HCHs did not change significantly during 1978-2003. In contrast, remarkable increasing trends of PBDEs and HBCDs were observed, suggesting growing consumption in Japan and surrounding countries in recent years.

Concentrations of persistent organic pollutants in masu salmon, Oncorhynchus masou.

The levels of persistent organic pollutants (POPs) were analyzed in muscle, liver and gills of masu salmon caught in northern Japan. Liver is known to be a major pool site for POPs but there is not much information regarding accumulation of POPs in gills. The salmon were caught at the end of the feeding migration, and the average gonadosomatic index of masu salmon was 0.51 +/- 0.16. The total amount of POPs (microg) accumulated in each organ was calculated in order to compare the accumulation potential of each organ. Even though the liver comprises only 1.8%-2.32% of the whole body mass it accumulated 16% +/- 8.6% of the total POPs. Similarly, gills comprise only 1.4%-2.1% of the body mass but accumulated 9.1% +/- 3.8% of the total POPs. Conversely, muscle comprises 72%-78% of the body mass and it accumulated 75% +/- 12% of the total POPs. These results suggest that the gills, in addition to the liver, are an important site for the pooling of high levels of POPs at the end of the feeding migration.

Possible role of a taurine transporter in the deep-sea mussel Bathymodiolus septemdierum in adaptation to hydrothermal vents.

Various invertebrates inhabiting hydrothermal vents possess sulfur-oxidizing bacteria in their tissues; however, the mechanisms by which toxic sulfides are delivered to these endosymbionts remain unknown. Recently, detoxification of sulfides using thiotaurine, a sulfur-containing amino acid, has been suggested. In this study, we propose the involvement of a taurine transporter in sulfide detoxification in the deep-sea mussel Bathymodiolus septemdierum by demonstrating: (i) the abundance of its mRNA in the gill; (ii) its activity under a wide range of salinities; (iii) its low Michaelis constant value in taurine transportation; and (iv) its affinity for thiotaurine and the thiotaurine precursor, hypotaurine.