Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu's parent body formed ~2 million years after the beginning of Solar System formation.

Investigation of immune complexes formed by mitochondrial antigens containing a new lipoylated site in sera of primary biliary cholangitis patients

Primary biliary cholangitis (PBC) is characterized by the presence of serum anti-mitochondrial autoantibodies (AMAs). To date, four antigens among the 2-oxo-acid dehydrogenase complex family, which commonly have lipoyl domains as an epitope, have been identified as AMA-corresponding antigens (AMA-antigens). It has recently been reported that AMAs react more strongly with certain chemically modified mimics than with the native lipoyl domains in AMA-antigens. Moreover, high concentrations of circulating immune complexes (ICs) in PBC patients have been reported. However, the existence of ICs formed by AMAs and their antigens has not been reported to date. We hypothesized that AMAs and their antigens formed ICs in PBC sera, and analyzed sera of PBC and four autoimmune diseases (Sjögren's syndrome, systemic lupus erythematosus, systemic scleroderma, and rheumatoid arthritis) using immune complexome analysis, in which ICs are separated from serum and are identified by nano-liquid chromatography-tandem mass spectrometry. To correctly assign MS/MS spectra to peptide sequences, we used a protein-search algorithm that including lipoylation and certain xenobiotic modifications. We found three AMA-antigens, the E2 subunit of the pyruvate dehydrogenase complex (PDC-E2), the E2 subunit of the 2-oxo-glutarate dehydrogenase complex (OGDC-E2) and dihydrolipoamide dehydrogenase binding protein (E3BP), by detecting peptides containing lipoylation and xenobiotic modifications from PBC sera. Although the lipoylated sites of these peptides were different from the well-known sites, abnormal lipoylation and xenobiotic modification may lead to production of AMAs and the formation ICs. Further investigation of the lipoylated sites, xenobiotic modifications, and IC formation will lead to deepen our understanding of PBC pathogenesis.

Genetically fused charged peptides induce rapid crystallization of proteins

We utilized electrostatic interaction to induce rapid crystallization of streptavidin. Simply mixing streptavidins possessing either a positively or negatively charged peptide at their C-terminus generated diffraction-quality crystals in a few hours. We modified the streptavidin crystals with fluorescent molecules using biotin, demonstrating the concept of protein crystals as functional biomaterials.

P3541Change in left ventricular ejection fraction and outcome in heart failure patients with mid-range ejection fraction: from the HIJ-HF prospective study

Introduction

Heart failure (HF) is categorized on the basis of the eft ventricular ejection fraction (LVEF). The European Society of Cardiology has proposed mid-range EF (HFmrEF) as a new category of HF that includes patients with an LVEF of 40–49%. However, the clinical characteristics, change in LVEF following treatment, and outcome of patients with HFmrEF remain clear.

Methods

We conducted a prospective observational study of Japanese hospitalized HF patients between 2015 and 2018 at a single-center (HIJ-HF III). HFmrEF was defined as 40–49% of LVEF on echocardiography at admission. We followed these patients and performed echocardiography to assess LVEF per year after hospital discharge. Clinical outcome was death from any cause.

Methods and results

We studied 138 patients with HFmrEF (median age 71 years, 69% male). They had 32% of ischemic heart disease, 9% of New York Heart Association functional class III or IV at discharge. During median follow-up of 20 [13–28] months, we assessed change in LVEF for 110 patients with HFmrEF. One year after hospital discharge, 49 patients (44%) improved LVEF (≥50%) and 21 patients (19%) reduced LVEF (<40%). HFmrEF patients who reduced LVEF (<40%) were significantly higher mortality rate than those who improved LVEF (≥50%) (14% vs. 2%, p<0.05) (Figure).

Conclusions

This study demonstrated that 44% of HFmrEF patients improved LVEF following treatment but 19% patients reduced LVEF. Reduced LVEF was associated with poor prognosis.

Interspecific and sexual differences in riverine distribution of tropical eels Anguilla spp

A total of 261 individuals of the four tropical eel species, Anguilla celebesensis, Anguilla marmorata, Anguilla bicolor pacifica and Anguilla interioris, were collected from 12 locations around Sulawesi Island, Indonesia, to gain knowledge about the riverine distribution of tropical eels. Anguilla marmorata was predominant in the lower reaches of Poso River (94·4% of total eel catch in the sampling area), Poso Lake (93·3%), three small inlet rivers of Tomini Bay (100%) and Laa River (92·3%). Anguilla celebesensis occurred frequently in the inlet rivers of Poso Lake (63·5%). Anguilla bicolor pacifica and Anguilla interioris were rare (1.5% and 0.4%, respectively). Otolith Sr:Ca ratio electron-probe micro analysis (EPMA) for individual migratory histories revealed that 15 A. celebesensis caught in Poso Lake and its inlet rivers were categorized into 14 river eels (Sr:Ca < 2·5) showing upstream migration seemingly at their elver stage and only one sea eel (Sr:Ca ≥ 6·0) that stayed in the marine habitat for the majority of its life after recruiting to Sulawesi Island before its late upstream migration. In A. marmorata, 19 examined eels from Poso Lake and its inlet rivers were all river eels, while 17 eels from the lower reaches of Poso River were two river eels, six sea eels and nine estuarine eels (2·5 ≤ Sr:Ca <6·0) that mostly lived in the brackish water. The sex ratio of A. celebesensis was highly skewed towards a dominance of females (99%). In A. marmorata, females were predominant in Poso Lake (95·2%), its inlet rivers (94·7%) and Laa River (100%), while males were more frequent in the lower reaches of Poso River (76·5%) and small inlet rivers of Tomini Bay (94·1%). These results indicate that the riverine distribution pattern of tropical eels differs among species and between sexes. This article is protected by copyright. All rights reserved.

Age and growth of migrating tropical eels, Anguilla celebesensis and Anguilla marmorata

The age and growth of migrating tropical eels, Anguilla celebesensis and Anguilla marmorata from central Sulawesi, Indonesia, were examined. Migrating eels (63 A. celebesensis and 38 A. marmorata) were obtained from weirs near the Poso Lake outlet and non-migrating eels (35 A. celebesensis and 119 A. marmorata) were captured by baited hooks, eel pots, scoop net and electro-fishing in the Poso River system, Laa River system, Baluga River, Tongku River and Padapu River from February 2009 to October 2010. In both species, the proportion of eels with opaque otolith edges showed a single peak in July, suggesting that one annulus (a pair of translucent and opaque zones) was formed each year in their otoliths. Mean ± s.d. and range of total length (L_T ) and age was 785·2 ± 114·9 (585-1083) mm and 7·5 ± 1·6 (5-11) years in migrating female A. celebesensis and 1132·2 ± 173·7 (800-1630) mm and 11·6 ± 3·3 (7-23) years in A. marmorata. The age of migrating female eels was negatively correlated with annual growth rate, 100·7 ± 17·2 (68·1-145·0) mm year^-1 in A. celebesensis and 97·9 ± 19·3 (66·6-131·6) mm year^-1 in A. marmorata, but there was no significant correlation between the L_T and annual growth rate in either species. The annual growth rates of these female tropical eels were typically higher than those of temperate anguillid species, suggesting a latitudinal cline in growth rate in the genus Anguilla reflecting the environmental conditions of their growth habitat.

Prolongation of somitogenesis in two anguilliform species, the Japanese eel Anguilla japonica and pike eel Muraenesox cinereus, with refined descriptions of their early development

The embryonic development of the Japanese eel Anguilla japonica and pike eel Muraenesox cinereus was morphologically investigated with laboratory-reared specimens to clarify the characteristics of somitogenesis. In A. japonica, somites were first observed at 18 h post fertilization (hpf) when epiboly reached 90%. Somitogenesis progressed at a rate of 1·6 h^-1 at mean ± s.d. 22·6 ± 0·7° C and completed at 107 hpf (3 days post hatching; dph) when total number of somites (ST) reached 114, which corresponds to the species' number of vertebrae (112-119). In M. cinereus, somites were first observed at 14 hpf when epiboly completed. Somitogenesis progressed at a rate of 1·9 h^-1 at mean ± s.d. 24·4 ± 0·2° C and completed at 90 hpf (2 dph) with 149 ± 4 ST, which corresponds to the species' number of vertebrae (142-158). Both species hatched before somitogenesis was completed, at 37 hpf with 47 ST and 42 hpf with 82 ± 4 ST, respectively. The formation of other organs such as the heart, mouth and pectoral fin bud occurred during somitogenesis. Comparison with the development of zebrafish Danio rerio indicates a prolongation of somitogenesis in A. japonica and M. cinereus. Their somitogenesis rates, however, correspond well with that of D. rerio estimated at the same temperature and their developmental stages at hatching are almost equivalent to other fishes having similar yolk sizes. Therefore, the prolongation of somitogenesis in A. japonica and M. cinereus may be accounted for solely by the increased numbers of somites to be formed, not by a slow somitogenesis rate or an acceleration in organogenesis.

Development of compartment for studies on the growth of protein crystals in space

To clarify the growth mechanism of a protein crystal, it is essential to measure its growth rate with respect to the supersaturation. We developed a compartment (growth cell) for measuring the growth rate (<0.1 nm s(-1)) of the face of a protein crystal at a controlled supersaturation by interferometry over a period of half a year in space. The growth cell mainly consists of quartz glass, in which the growth solution and a seed crystal are enclosed by capillaries, the screw sample holder, and a helical insert. To avoid the destruction of the cell and the evaporation of the water from the solution inside the cell, we selected the materials for these components with care. The equipment was successfully used to examine the growth of a lysozyme crystal at a controlled supersaturation in space, where convection is negligible because of the microgravity environment, thereby advancing our understanding of the mechanism of protein crystal growth from solution. The technique used to develop the growth cell is useful not only for space experiments but also for kinetic studies of materials with very slow growth and dissolution rates (<10(-3) nm s(-1)).

Weight change after 20 years of age and the incidence of dyslipidemia: a cohort study of Japanese male workers

BACKGROUND

While heavier weight is known to increase the incidence of dyslipidemia, limited data are available on the relationship between weight gain and its development.

METHODS

A total of 2647 males were categorized into the following four groups according to the difference between their self-reported weight at 20 years of age and their measured weight in 1994-95: a loss of ≥5% (decrease), loss of <5% or gain of <5% (no change), gain of ≥5 to <15% (increase) and gain of ≥15% (sizable increase). They were followed up until their 2002-03 health examination. Using the 'no change' group as reference, the multivariable-adjusted odds ratio (adjusted for age, body mass index at 20 years of age, physical activity, smoking and alcohol intake) and 95% confidence interval (95% CI) for the incidence of dyslipidemia were determined using logistic regression models.

RESULTS

A total of 1342 participants developed dyslipidemia during the follow-up period. The 'increase' and 'sizable increase' groups had odds ratios for the incidence of dyslipidemia of 1.97 (95% CI, 1.59-2.45) and 2.68 (2.15-3.34), respectively, demonstrating that there was a significant dose-response association between weight gain since 20 years of age and the incidence of dyslipidemia (P < 0.001 for trend).

CONCLUSION

These results suggest that dyslipidemia could be prevented by avoiding weight gain in adulthood.

Head-shape polymorphism in Japanese eels Anguilla japonica in relation to differences of somatic growth in freshwater and brackish habitats

The age, total length (L(T)), head shape and skull shape were investigated for 379 Japanese eels Anguilla japonica sampled in freshwater and brackish areas of the Kojima Bay-Asahi River system, Okayama, Japan, to learn about the differentiation process of head-shape polymorphism. The relative mouth width (ratio of mouth width to L(T)) of A. japonica > 400 mm L(T) collected in fresh water was significantly greater than that of fish collected in brackish water. Growth rates of mouth width and the distance from the snout to the midpoint of the eyes (the ratio of width and distance to age, respectively) were not significantly different between freshwater and brackish-water samples, whereas the somatic growth rate (the ratio of L(T) to age) of freshwater samples was significantly lower than that of brackish-water eel samples. These results suggest that the factors affecting head and somatic growth of A. japonica are not identical. According to these results and feeding patterns in each habitat reported by another study, it is suggested that somatic growth appears to play a significant role in the differentiation process of the head-shape polymorphism in A. japonica, with the slow-growing fish in fresh water becoming broad-headed and the fast-growing fish in brackish water becoming narrow-headed.

Non-genomic inhibitory effect of glucocorticoids on activated peripheral blood basophils through suppression of lipid raft formation

We investigated the non-genomic effects of glucocorticoids (GCs) on inhibition of plasma membrane lipid raft formation in activated human basophils. Human basophils obtained from house dust mite (HDM)-sensitive volunteers were pretreated with hydrocortisone (CORT) or dexamethasone (Dex) for 30 min and then primed with phorbol 12-myristate 13-acetate (PMA, 10 ng/ml) or HDM (10 µg/ml). The expression of CD63, a basophil activation marker, was assessed by flow cytometry. Membrane-bound GC receptors (mGCRs) were analysed by flow cytometry and confocal laser microscopy. Lipid rafts were assessed using a GM1 ganglioside probe and visualization by confocal laser microscopy. Pretreatment of basophils with CORT (10(-4) M and 10(-5) M) and Dex (10(-7) M) significantly inhibited CD63 expression 20 min after addition of PMA or HDM. The inhibitory effects of GCs were not altered by the nuclear GC receptor (GCR) antagonist RU486 (10(-5) M) or the protein synthesis inhibitor cycloheximide (10(-4) M) (P < 0·05). CORT coupled to bovine serum albumin (BSA-CORT) mimicked the rapid inhibitory effects of CORT, suggesting the involvement of mGCRs. mGCRs were detectable on the plasma membrane of resting basophils and formed nanoclusters following treatment with PMA or HDM. Pretreatment of cells with BSA-CORT inhibited the expression of mGCRs and nanoclustering of ganglioside GM1 in lipid rafts. The study provides evidence that non-genomic mechanisms are involved in the rapid inhibitory effect of GCs on the formation of lipid raft nanoclusters, through binding to mGCRs on the plasma membrane of activated basophils.

Chronic effect of training on neutrophil functions in humans

We performed this study to evaluate the chronic effect of training on neutrophil functions in humans. Twenty-six university students (14 males and 12 females) with a mean age of 19.1±0.8 years were divided into the athlete group and the control group based on answers given to a written questionnaire. The capacity of circulating neutrophils to ingest bacteria (phagocytosis) and to produce superoxide (nitroblue tetrazolium reduction) was measured under resting conditions in the absence of training activities. In addition, we measured hematological and serum biochemical parameters.The present analyses revealed that the frequency of subjective symptoms concerning susceptibility to infections (sum of males and females) was higher in the athlete group than in the control group (p<0.05). In the investigation of males, hemoglobin and serum protein levels of the athlete group were lower than that of the control group (p<0.01, p<0.05, respectively). Although total and differential leukocyte counts, and phagocytic activity of neutrophils were not significantly different between the groups, superoxide productivity of neutrophils in the male athlete group was higher than that in the control group (p<0.05).Since significant differences were observed in hemoglobin and serum protein levels in the male athletes, the training is considered to have been intense. An increase was noted in the neutrophil superoxide production along with these changes, but no significant difference was observed in the phagocytic activity. Therefore, there is the possibility of superoxide overproduction, which may lead to tissue damage.

Quantification of chicken anaemia virus by competitive polymerase chain reaction

A quantitative method for chicken anaemia virus (CAV) was developed using competitive polymerase chain reaction (PCR). Competitive template was constructed by deletion of 33 nucleotides from a wildtype DNA clone of CAV. Quantification of CAV DNA molecules by the competitive PCR was rapid and highly reproducible when compared with conventional infectivity titration methods. The ratios of the viral DNA molecules and infectivity titres in MDCC-MSB1 cells varied between 1.3 and 3.55 log(10) among several isolates, suggesting the existence of different infection efficiencies to MDCC-MSB1 cells by isolates. The competitive PCR will be useful for studying CAV infection in vivo and/or in vitro.

The Anguilla spp. migration problem: 40 million years of evolution and two millennia of speculation

Anguillid eels Anguilla spp. evolved between 20 and 40 million years ago and possess a number of remarkable migratory traits that have fascinated scientists for millennia. Despite centuries of effort, the spawning areas and migrations are known only for a few species. Even for these species, information on migratory behaviour is remarkably sketchy. The latest knowledge on the requirements for successful migration and field data on the migrations of adults and larvae are presented, how experiments on swimming efficiency have progressed the understanding of migration are highlighted and the challenges of swimming at depth considered. The decline of Anguilla spp. across the world is an ongoing concern for fisheries and environmental managers. New developments in the knowledge of eel migration will, in addition to solving a centuries old mystery, probably help to identify how this decline might be halted or even reversed.

Morphological and physiological changes of female tropical eels, Anguilla celebesensis and Anguilla marmorata, in relation to downstream migration

The morphological and physiological characteristics of migrating and non-migrating female tropical eels, Anguilla celebesensis and Anguilla marmorata were examined in relation to their downstream migration on central Sulawesi Island, Indonesia. Migrating eels (64 A. celebesensis and 37 A. marmorata) were obtained from weirs set near the outlet area of Poso Lake and non-migrating eels (21 A. celebesensis and 21 A. marmorata) were sampled by set-lines and eel pots in Poso Lake, its inlet rivers, and in the La River system during February 2009 to October 2010. In both species, values of eye index, pectoral-fin length index, gonado-somatic index (I(G)), hepato-somatic index, swimbladder-somatic index and cardio-somatic index of migrating eels were significantly higher than those of non-migrating eels and the gut-somatic index values of the migrating eels were significantly lower than that of non-migrating eels. When silvering stages of eels were classified by the silvering index for Anguilla japonica, in A. celebesensis, all non-migrating eels were Y1 stage and the migrating eels consisted of Y2, S1 and S2 stages eels. In A. marmorata, the non-migrating eels consisted of Y1 and Y2 eels, and the migrating eels consisted of Y2 and S1 eels, but there were no S2 eels. Results of principal component analysis (PCA) of morphological and physiological variables suggested that these characteristics changed drastically between the Y1 and Y2 stages in A. celebesensis, while A. marmorata showed a gradual change with silvering, which differs from the temperate species A. japonica. The mean ±S.D. I(G) value of migrating A. celebesensis (6.9 ± 1.8, 3.3-11.4) was very high and that of A. marmorata (3.1 ± 0.8, 1.8-5.7) was comparatively low. The very different rates of maturation that were found between these two species provide support for the hypothesis that the reproductive characteristics of silver eels can reflect their migration scale.

Habitat segregation and biochemical activities of marine members of the family vibrionaceae

A comparative study of marine members of the family Vibrionaceae with the technique of numerical taxonomy revealed habitat segregation as well as a cosmopolitan nature of species distribution among the vibrios in different marine environments. The bacterial strains analyzed were isolated from seawater, sediments, phyto- and zooplankton, and fish in the Indian Ocean, the South and East China Sea, and West Pacific Ocean, and coastal areas of Japan. A total of 155 morphological, physiological, and biochemical tests were carried out for each of 405 strains examined. The results showed that most of the large taxonomical clusters which emerged from the computation corresponded to ecological groups which have particular niches. For instance, each group of seawater vibrios inhabited a particular water layer of limited depth range, in spite of the fact that strains of the group were isolated from sampling locations spread over a wide area from the Indian Ocean to Japanese coast. Various vibrio groups showed remarkable differences in their physiological and biochemical activities, and the activities of each group seemed to correspond with its ecological niche. The strains which inhabited surface-water layers grew fast and actively utilized many high-molecular-weight organic compounds and carbohydrates that are derived from fresh, easily degradable organic matter present in the surface waters, whereas the middle- and deep-water vibrios did not decompose most of the high-molecular-weight organic compounds except chitin but, rather, utilized some carbohydrates and organic acids which seemed to be derived from refractory particulate organic matter present in the deeper waters.

The perfusion index derived from a pulse oximeter for predicting low superior vena cava flow in very low birth weight infants

OBJECTIVE

Superior vena cava (SVC) flow is used as an index for evaluating systemic blood flow in neonates. Thus far, several reports have shown that low SVC flow is a risk factor for intraventricular hemorrhage (IVH) in the preterm infant. Therefore, it is likely to be a useful index in the management of the preterm infant. The perfusion index (PI) derived from a pulse oximeter is a marker that allows noninvasive and continuous monitoring of peripheral perfusion. The objective of this paper was to determine the accuracy of the PI for detecting low SVC flow in very low birth weight infants born before 32 weeks of gestation.

STUDY DESIGN

We studied the correlation between PI and SVC flow 0 to 72 h after birth in very low birth weight infants born before 32 weeks of gestation. The best cut-off value for low SVC flow was calculated from the respective receiver-operating characteristic curves.

RESULT

A positive correlation was found between the PI and SVC flow (r=0.509, P<0.001). The best cut-off value for the PI to detect low SVC flow was 0.44 (sensitivity 87.5%, specificity 86.3%, positive predictive value 38.9%, negative predictive value 98.6%).

CONCLUSION

This study found that the PI was associated with SVC flow, and it was a useful index for detecting low SVC flow in very low birth weight infants born before 32 weeks of gestation. Therefore, use of the PI should be evaluated in the cardiovascular management of the preterm infant.

Influence of water temperature and feeding regime on otolith growth in Anguilla japonica glass eels and elvers: does otolith growth cease at low temperatures?

The influences of water temperature and feeding regime on otolith growth in Anguilla japonica glass eels and elvers were investigated using individuals reared at 5, 10, 15, 20, 25 and 30 degrees C and in fed or unfed conditions at salinity 32 after their otoliths were marked with alizarin complexone (ALC). To eliminate the difficulty of observing the edges of otoliths with optical (OM) or scanning electron (SEM) microscopes, three to 10 individuals were sampled from each tank at 10, 20 and 30 days during the experiment and reared for an additional 10 days at 25 degrees C after their otoliths were marked a second time. Otolith growth and the number of increments were measured using both OM and SEM. Most A. japonica commenced feeding after 10 days at 20-30 degrees C or after 20 days at 15 degrees C, but no feeding occurred at 5 and 10 degrees C. No otolith growth occurred at 5 and 10 degrees C except in two individuals with minimal increment deposition at 10 degrees C. Otolith growth was proportional to water temperature within 15-25 degrees C and not different between 25 and 30 degrees C. At 15, 25 and 30 degrees C, the mean otolith growth rate in fed conditions was higher than in unfed conditions. The number of increments per day was significantly different among water temperatures (0.00-0.01 day(-1) at 5 and 10 degrees C, 0.43-0.48 day(-1) at 15 degrees C and 0.94-1.07 day(-1) at 20-30 degrees C). These results indicated that otolith growth in A. japonica glass eels and elvers was affected by temperature and ceased at < or =10 degrees C under experimental conditions. Hence, future studies analysing the otoliths of wild-caught A. japonica glass eels and elvers need to carefully consider the water temperatures potentially experienced by the juveniles in the wild.

Sympatric spawning of Anguilla marmorata and Anguilla japonica in the western North Pacific Ocean

Extensive collections were made of the larvae of the temperate Japanese eel Anguilla japonica and the tropical giant mottled eel Anguilla marmorata in an overlapping area of the North Equatorial Current region of the western North Pacific Ocean. Collections of 189 A. marmorata and > 2500 A. japonica larvae during nine surveys from 1991 to 2007 showed that these two anguillid eels have similar spawning areas just west of the southern West Mariana Ridge. In July to August 2006 and August 2007, morphologically and genetically identified A. marmorata preleptocephali were mainly collected between 14.5-15 degrees N and 142-142.5 degrees E, where A. japonica preleptocephali were also caught in some of the same net tows. Fewer A. marmorata preleptocephali, however, were collected (n = 31) compared to those of A. japonica (n = c. 165), and fewer small larvae of A. marmorata were collected per tow than A. japonica (n = 1-10 and 1-294, respectively), suggesting relatively smaller spawning aggregations of A. marmorata. The distribution of preleptocephali and small larvae was wider in longitude in A. marmorata (131- 143 degrees E) than in A. japonica (137-143 degrees E), while the latitudinal range was almost the same (12-17 degrees N). Although spawning by these two species overlaps both spatially and temporally, the tropical eels of the North Pacific population of A. marmorata probably have a much longer spawning season with fewer spawners, at least in summer, and recruit to a much wider latitudinal range of growth habitats.

Oceanic migration and spawning of anguillid eels

Many aspects of the life histories of anguillid eels have been revealed in recent decades, but the spawning migrations of their silver eels in the open ocean still remains poorly understood. This paper overviews what is known about the migration and spawning of anguillid species in the ocean. The factors that determine exactly when anguillid eels will begin their migrations are not known, although environmental influences such as lunar cycle, rainfall and river discharge seem to affect their patterns of movement as they migrate towards the ocean. Once in the ocean on their way to the spawning area, silver eels probably migrate in the upper few hundred metres, while reproductive maturation continues. Although involvement of a magnetic sense or olfactory cues seems probable, how they navigate or what routes they take are still a matter of speculation. There are few landmarks in the open ocean to define their spawning areas, other than oceanographic or geological features such as oceanic fronts or seamounts in some cases. Spawning of silver eels in the ocean has never been observed, but artificially matured eels of several species have exhibited similar spawning behaviours in the laboratory. Recent collections of mature adults and newly spawned preleptocephali in the spawning area of the Japanese eel Anguilla japonica have shown that spawning occurs during new moon periods in the North Equatorial Current region near the West Mariana Ridge. These data, however, show that the latitude of the spawning events can change among months and years depending on oceanographic conditions. Changes in spawning location of this and other anguillid species may affect their larval transport and survival, and appear to have the potential to influence recruitment success. A greater understanding of the spawning migration and the choice of spawning locations by silver eels is needed to help conserve declining anguillid species.

Morphological and meristic evaluation of the population structure of Anguilla marmorata across its range

The population structure of the giant mottled eel Anguilla marmorata was evaluated using statistical analysis of 21 morphological characters among 13 representative localities across the Indo-Pacific region and as far north as Japan. There were no clear differences in 15 proportional and six vertebral characters using principal component analysis. The total number of vertebrae (N(V)) of A. marmorata at these localities had the widest variation among the morphological and meristic characters examined. A statistical analysis of the N(V) of 1238 specimens from 14 localities that included previously published data found significant differences among Micronesia, French Polynesia and other localities, and between localities in the North Pacific and South Pacific regions. Few differences were detected between specimens from the Indian Ocean and the North Pacific or South Pacific regions. The differences in N(V) among some regions and the population genetic studies of this species indicate that there are at least four populations of A. marmorata (North Pacific, Micronesia, Indian Ocean and South Pacific), which appear to include metapopulation structures in the Indian Ocean and South Pacific. This population structure is consistent with the ocean current patterns in each region and the evolution of migration loops of each spawning population.

Depth distribution and biological characteristics of the European eel Anguilla anguilla in Lough Ennell, Ireland

Using a longline survey, a total of 196 European eels Anguilla anguilla were collected at different depths in Lough Ennell (maximum depth 30 m), central Ireland. The catch per unit of effort of A. anguilla that were caught from 1 to 25 m depths was lowest at 0.5-5.0 m and greatest at the deepest depth range (22.5-25.0 m). Sub-samples of A. anguilla from depths of <15 m showed little or no difference in size, sex ratio, age, growth rate, condition factor, length-mass relationship, gonado-somatic index, fin index or eye index with fish from depths of >15 m. All fish examined were female yellow-phase A. anguilla that had ages from 7 to 20 years (mean +/-s.d. = 10.3 +/- 2.9 years), with growth rates from 24.0-60.8 mm year(-1) (mean +/-s.d. = 40.7 +/- 8.5 mm year(-1)). Variations in the growth rates were greater in the shallow group than that of the deep group. This study suggested that deeper regions are important feeding habitats for A. anguilla and that fish in this lake were growing moderately fast compared to similar habitats and areas in the species' range.

Isolation of Marek's disease virus from Japanese quail with lymphoproliferative disease

Sixty-one Japanese quail from eight flocks with problems of recurring outbreaks of lymphoproliferative diseases resembling Marek's disease (MD), were examined aetiologically. Gross lymphomatous lesions were seen in 17 of the quail and 11 out of 56 quail had MD virus (MDV) feather tips antigens. MDV antibody was detectable in only one of 22 quail. None of 9 quail had antibodies against reticuloendotheliosis virus (REV). No MDV was isolated from the total 42 materials of quail using cell culture technique. No REV and avian leukosis virus (ALV) were isolated from some of them. However, specific-pathogen-free chicks inoculated with the blood materials revealed MD. and four MDVs were recovered from them. The isolates proved free from REV and ALV. The isolates were placed into serotype 1 by the indirect immunofluorescent antibody test. These results indicate that MDV is aetiologically involved in the present outbreaks of lymphoproliferative disease in Japanese quail.

Endogenous acyl ghrelin is involved in mediating spontaneous phase III-like contractions of the rat stomach

In humans and dogs, it is known that motilin regulates phase III contractions of migrating motor complex (MMC) in the fasted state. In rats, however, motilin and its receptor have not been found, and administration of motilin failed to induce any phase III-like contractions. Ghrelin was discovered as the endogenous ligand for the growth hormone secretagogue receptor (GHS-R) from the rat stomach. Ghrelin promotes gastric premature phase III (phase III-like contractions) in the fasted state in rats. We hypothesized that endogenous ghrelin regulates spontaneous phase III-like contractions in rats. Strain gauge transducer was sutured on the antrum and a catheter was inserted into the jugular vein. We studied the effects of i.v. administration of ghrelin and a GHS-R antagonist on gastric phase III-like contractions in conscious rats. Plasma level of ghrelin was measured by a radioimmunoassay. Ghrelin augmented spontaneous phase III-like contractions and a GHS-R antagonist significantly attenuated the occurrence of spontaneous phase III-like contractions. During the phase I period, plasma ghrelin level increased to its peak then returned to basal level, subsequently phase III-like contractions were observed. These results suggest that endogenous ghrelin regulates gastric phase III-like contractions in rats.