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

Elemental composition in otoliths of surfperch, Ditrema temmincki

The elemental composition of the otolith was examined in both male and female surfperch, Ditrema temmincki. The determined concentrations of 22 elements were the same regardless of the fish\u27s sex. K, Mg, and Na which are major elements in seawater, accumulations from seawater to otolith of those elements were quite smaller than other minor elements. This suggests that elemental discrimination might occur during the movement from blood plasma to endolymph after the branchial uptake from ambient water

Biological effects of low concentrations of tributyltin on the caprellid amphipod Caprella danilevskii

In order to examine the biological effects of tributyltin (TBT), experiments involving the exposure of 5 levels of TBT concentrations (0, 10, 100, 1000 and 10000 ngl^) were conducted on the caprellid amphipod Caprella danilevskii, both over a generation after hatching (50 days) and embryonic stage (5 days). In TBT exposure after hatching, marked delays in growth and molting during the early developmental stage and mature stage were found in both 100 and 1000ng TBTCll^ concentrations in spite of the sex. All specimens died in 10000 ng TBTCll^ within 4 days after hatching. Inhibition of maturation and reproduction such as delaying in the achievement of maturity and a decrease in the number of juveniles hatched was apparent in 10 and 100ng TBTCll^ concentrations. Furthermore, brood loss, and failure in egg formation and hatching were observed as the TBT concentration became higher. No significant changes in sex ratio were seen in response to TBT exposure after hatching. A drastic decrease in survival rate was observed at 10ng TBTCll^ which corresponds to the mean level in coastal waters. In embryonic exposure, although the female proportion was 36% of the total in the control, its proportion increased up to 80% at 100 and 1000ngl^ in the hatched juvenile. All specimens died in 10000 ngTBTCll^ within 5 days after spawning due to the acute toxic concentration for the species. No significant differences were observed to occur in the sex ratio in response to the exposure after hatching (50 days) in a previous study. Sex disturbance might therefore be induced during the embryonic stage in the caprellid. Reproductive inhibitions such as brood loss and oogenesis inhibition occurred even at 10-100 ng TBTCll^ exposures in the short-term period in both parental females and their offspring females. The embryo survival rate in the offspring decreased drastically as the TBT concentrations increased, with the decrease being observed at TBT concentrations as low as 10ngl^ during 5 days. In parental females, the survival rate also decreased at more than 100ng TBTC ll^, despite transfer into the no TBT-added seawater after 5 days. Therefore, our data suggest that nanogram concentrations TBT exposure, both short- and long-term, in the coastal environment might critically damage the life history characters of caprellids, and may influence populations of C. danilevskii in the coastal ecosystem

Mediatory Summary Generation: Summary-Passage Extraction for Information Credibility on the Web

PACLIC 23 / City University of Hong Kong / 3-5 December 200

Microscopic Temperature Control Reveals Cooperative Regulation of Actin–Myosin Interaction by Drebrin E

胎児の神経を形作る仕組みは精密な温度センサー --母体の体温維持が神経の成熟に重要であることを示唆--. 京都大学プレスリリース. 2021-11-10.Drebrin E is a regulatory protein of intracellular force produced by actomyosin complexes, that is, myosin molecular motors interacting with actin filaments. The expression level of drebrin E in nerve cells decreases as the animal grows, suggesting its pivotal but unclarified role in neuronal development. Here, by applying the microscopic heat pulse method to actomyosin motility assay, the regulatory mechanism is examined from the room temperature up to 37 °C without a thermal denaturing of proteins. We show that the inhibition of actomyosin motility by drebrin E is eliminated immediately and reversibly during heating and depends on drebrin E concentration. The direct observation of quantum dot-labeled drebrin E implies its stable binding to actin filaments during the heat-induced sliding. Our results suggest that drebrin E allosterically modifies the actin filament structure to regulate cooperatively the actomyosin activity at the maintained in vivo body temperature

Environmental history of Japanese eel, Anguilla japonica collected in Miyako Bay, northeastern Japan

The environmental history in combination with age of the Japanese eel, Anguilla japonica, collected in Miyako Bay along the Sanriku Coast of Japan, was examined using the otolith microstructure and analysis of strontium (Sr) and calcium (Ca) concentrations with wavelength dispersive X-ray spectrometry by an electron microprobe. The line analysis of Sr : Ca ratios along the life history transect of each otolith showed a peak (ca 12-17×10^) between the core and elver mark, which corresponded to the period of their leptocephalus and early glass eel stages in the ocean. The mean Sr : Ca ratios from the elver mark to the otolith edge indicated that there were eels with several general categories of migratory history, that included sea eels that never entered freshwater (average Sr : Ca ratios, >6.0×10^) and others that had entered freshwater for brief periods, but returned to the estuary or bay. This evidence of the occurrence of sea eels indicates that Japanese eels in this northern area do not necessarily migrate into freshwater rivers during recruitment as glass eels at the beginning of their growth phase, and even those that do enter freshwater may later return to the marine environment

Impact of Gestational Age at Delivery on Fetal Heart Rate Monitoring During the Second Stage of Labor

Objective: To clarify whether gestational age at delivery affects the interpretation level of fetal heart rate (FHR) tracings in the second stage of labor in primiparous and singleton pregnancies.Methods: The database at one tertiary hospital in Japan was retrospectively reviewed for women with singleton fetuses in cephalic presentation and vaginal labor at ≥37+0 gestational weeks between June 1, 2011, and March 31, 2013. Continuous FHR tracings in the second stage of labor were subdivided into 10-minute intervals, each of which we called a window, from the beginning through delivery, and were assessed according to the five-tier classification proposed by the Japan Society of Obstetrics and Gynecology, in which level 1 is normal, level 2 is subnormal, and levels 3-5 are abnormal patterns. Subjects were divided into two groups, including early term (37 0/7 to 38 6/7 weeks) and full term (39 0/7 to 41 6/7 weeks), according to the delivery age.Results: In total, 914 parturient women were eligible for the study protocol, including 228 and 686 women in early and full term, respectively. Vacuum extraction was more often observed in full term than in early term (P=0.007). Although the maximal level, number of level-5 windows, number of level-4 windows, and number of level-3 and level-4 windows were similar between the groups, the summation of level-4 windows ≥3 was significantly higher in full term than in early term (P=0.004).Conclusion: Full term delivery has a higher risk than does early term delivery from the standpoint of FHR monitoring

Effects of tributyltin on the chlorophyll contents of marine microalga Tetraselmis tetrathele, Nannochloropsis oculata and Dunaliella sp

Three species of marine microalga Tetraselmis tetrathele, Nannochloropsis oculata and Dunaliella sp., the important phyto-plankton in many hatcheries, were used in an acute toxicity test of TBT with emphasis on the chlorophyll a and b contents. After a very short exposure time of three concentrations of TBT, 0.1, 0.5 and 1μgl^, the three species of algae showed different responses. The chlorophyll a and b contents of T. tetrathele in all treatments were higher than those in controls, even be doubled in 1μgl^ of TBT. N. oculata and Dunaliella had a slightly higher chlorophyll a and b contents in the lowest TBT concentration tested (0.1μgl^) than those in control, but as the TBT concentration increased their chlorophyll contents decreased. Three levels of TBT tested are within the range of the no observable effect concentration (NOEC) for T. tetrathele, while the lowest observable effect concentrations (LOEC) for N. oculata and Dunaliella are between 0.1 to 0.5μgl^. Among the three species, N. oculata has a highest sensitivity towards TBT

Suzaku Observation of Abell 1689: Anisotropic Temperature and Entropy Distributions Associated with the Large-Scale Structure

(Abridged) We present results of Suzaku observations of the intracluster medium (ICM) in Abell 1689, combined with complementary analysis of the SDSS data and weak and strong lensing analysis of Subaru/Suprime-Cam and HST/ACS observations. Faint X-ray emission from the ICM around the virial radius is detected at 4.0 sigma significance. We find anisotropic gas temperature and entropy distributions in cluster outskirts correlated with large-scale structure of galaxies. The high temperature and entropy region in the northeastern (NE) outskirts is connected to an overdense filamentary structure. The outskirt regions in contact with low density void environments have low gas temperatures and entropies, deviating from hydrostatic equilibrium. These results suggest that thermalization of the ICM occurs faster along the filamentary structures than the void regions. A joint X-ray and lensing analysis shows that the hydrostatic mass is $\sim60-90$ of spherical lensing one but comparable to a triaxial halo mass within errors in 0.6r_{2500} \simlt r \simlt 0.8r_{500}, and that it is significantly biased as low as \simlt60% within $0.4r_{2500}$, irrespective of mass models. The thermal gas pressure within $r_{500}$ is, at most, $\sim50$--60% of the total pressure to balance fully the gravity of the spherical lensing mass, and $\sim30$--40% around the virial radius. Although these constitute lower limits when one considers the possible halo triaxiality, these small relative contributions of thermal pressure would require additional sources of pressure, such as bulk and/or turbulent motions.Comment: 24 pages, 15 figures, 9 tables. Accepted for publication in Ap

Effects of triphenyltin exposure on the red alga Eucheuma denticulatum

Toxic effects of triphenyltin (TPT) on the marine alga Eucheuma denticulatum obtained from Nain Island, North Sulawesi, Indonesia have been examined in laboratory condition. The algal samples were first acclimated in laboratory prepared seawater for three days. The algae were then divided into 12 culture chambers for treatments with different concentrations of TPT between 5-30 μgl^ with 5μgl^ interval, and in another container for control. After two-week experimentation, some samples of algae were obtained from each chamber for histopathological examination. The aniline blue stained tissue of alga E. denticulatum showed that at all TPT concentration tested, the cortex had morphological changes, even almost disappeared at higher concentration (>20μgl^). The medullary cells of alga exposed to 5-15μgl^ have been decreasing in size compared to those in control. Cell walls of some medullary cells have damaged at 20μgl^ and totally lysed in all cells of alga exposed to 25 and 30μgl^. The pattern of zonatedly dividing tetrasporangium had not occurred anymore in alga exposed to TPT even at the lowest tested concentration (5μgl^) and had totally damaged in higher concentrations, such as that of 20μgl^. The tetraspores in tetrasporangium seem to be fused or shrinkage, no more dividing process occurred as in control. Therefore, reproductive cells of alga is more sensitive than somatic cells, indicating that no further development of alga will occur in aquatic environment contaminated even with unlethal TPT levels