A survey for leptocephali around Sulawesi Island in the central Indonesian Seas during May 2001 found that the leptocephali
of the congrid eel, Ariosoma scheelei, were present in all seven areas that were sampled. A total of 551 leptocephali (22–166 mm TL) were collected, and A. scheelei was by far the most abundant species of leptocephali collected during the survey. The wide range of sizes in most areas indicated
that spawning had occurred during a period of several months in many different areas, although the exact spawning locations
were not determined. The larger size classes were more abundant in all areas except in Tomini Bay on the northeast side of
Sulawesi Island. The highest catch rates were observed at the eastern edge of the Java Sea and to the north in the Celebes
Sea near Makassar Strait. Premetamorphic leptocephali were also collected in surface samples at 11 stations (N=62), but metamorphosing leptocephali (N=86) were only caught in IKMT tows that fished from the surface to about 200 m. Metamorphosing leptocephali were collected
primarily at two stations in the Java Sea and Makassar Strait where a surface layer of lower-salinity water was detected.
Their total lengths (105.3–153.3 mm) and the largest premetamorphic individuals suggested that this species can reach maximum
sizes of about 165 mm before beginning to metamorphose. It is hypothesized that this species may be abundant in the Indonesian
Seas region and that it has ecological traits such as large size at recruitment and a small size at reproduction that have
made it successful in many regions of the Indo-Pacific. 相似文献
The spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) has become an increasingly serious global public health issue. This study investigated the distribution characteristics and influencing factors of ARB and ARGs in greenhouse vegetable soils with long-term application of manure. Five typical ARGs, four heavy metal resistance genes (MRGs), and two mobile genetic elements (MGEs) were quantified by real-time quantitative polymerase chain reaction (qPCR). The amount of ARB in manure-improved soil greatly exceeded that in control soil, and the bacterial resistance rate decreased significantly with increases in antibiotic concentrations. In addition, the resistance rate of ARB to enrofloxacin (ENR) was lower than that of tylosin (TYL). Real-time qPCR results showed that long-term application of manure enhanced the relative abundance of ARGs in vegetable soils, and the content and proportion of quinolone resistance genes were higher than those of macrolide resistance genes. Redundancy analysis (RDA) showed that qepA and qnrS significantly correlated with total and available amounts of Cu and Zn, highlighting that certain heavy metals can influence persistence of ARGs. Integrase gene intI1 correlated significantly with the relative abundance of qepA, qnrS, and ermF, suggesting that intI1 played an important role in the horizontal transfer of ARGs. Furthermore, there was a weakly but not significantly positive correlation between specific detected MRGs and ARGs and MGEs. The results of this study enhance understanding the potential for increasing ARGs in manure-applied soil, assessing ecological risk and reducing the spread of ARGs.
This paper reports the effects of a placebo-controlled Se-enriched yeast supplementation trial, conducted for 14 months, on arsenism in adult farmers living in a rural community in Inner Mongolia, China. The farmers had been naturally exposed to elevated concentrations of As in drinking water from tube-wells since 1983 but changed to arsenic-free drinking water when the trial began in June 1996. Blood and hair Se and As concentrations were analysed pre-intervention and at the end of the 3rd, 9th and 14th month, while skin lesions were assessed pre-intervention, as well as at the end of the 14th month, using the Arsenism Clinical Criteria established by the Ministry of Health, China. As the trial was a voluntary one, a number of farmers did not routinely have their blood and hair samples taken for analysis. Consequently, the data have been analysed in two categories. Fifty-four farmers from the Se-group and 29 from the placebo-group who were sampled on each occasion were considered as one group, which has been compared with the second group comprising up to a total of 100 farmers in the Se-group and 86 in the placebo-group. Results calculated for those farmers who were sampled on each occasion, showed that at the end of the trial, blood and hair Se concentrations of the Se-group increased from 0.130 to 0.186 µg ml–1 and from 0.431 to 0.502 µg g–1, respectively, while those of the placebo-groups remained constant. Blood and hair As concentrations of the Se-group decreased from 0.051 to 0.015 µg ml–1 and from 2.57 to 0.680 µg g–1, respectively, a greater reduction than those in the placebo-group that went from 0.064 to 0.024 µg ml–1 and from 2.62 to 1.25 µg g–1, respectively. When the data from all patients were examined, the analytical trends were similar. An evaluation of skin lesions in the category who were sampled for hair and blood on each occasion showed that 41.2% of hyperkeratosis, 50.0% of depigmentation and 44.7% of pigmentation in the Se-group improved one or more degrees, while those in the placebo-group improved by only 7.1, 12.0 and 6.7%, respectively. A total of 61.1% of the adults in Se-group improved in one or more type of skin lesion, but only 17.2% improved in the placebo-group. Comparable results were obtained when all the data from both categories of farmers were examined. Results from the trial showed that Se supplementation was more effective for the improvement of adults who were affected by double or triple skin lesions. In the placebo-group, most of the severely affected adults improved in only one kind of skin lesion, but in the Se-group, more adults improved in two or three kinds of skin lesions. Although the trial was limited by its relatively small size, the results have provided some evidence of the usefulness of Se supplementation for people affected by arsenism. 相似文献
The clinical skin lesions of arsenism in men and women in Bayinmaodao rural district in Inner Mongolia, Peoples Republic of China, have been examined by doctors, and their hair and drinking water samples analysed for arsenic by hydride generation and ICP-AES. Altogether 311 arsenism patients with a 15.53% prevalence rate for the district were recorded. The disease prevalence rate was positively related to population, age, and their exposure to elevated arsenic concentrations in the drinking water from 1983 when new wells were dug and drinking of surface water was abandoned. Hyperkeratosis was the most serious skin lesion with the highest occurrence rate, then depigmentation and pigmentation in decreasing order. With increasing severity of the disease, ranging from skin lesion with single hyperkeratosis 1° to hyperkeratosis 3° with depigmentation 3° and pigmentation 3°, the results showed that arsenic concentrations in head hair had increased. Arsenic concentrations in hair were positively correlated with the arsenic concentrations in drinking water obtained from local wells. 相似文献
In order to elucidate the evolutionary process of deep-sea Bathymodiolus mussels, we investigated the phylogenetic relationships of 16 species worldwide by analyzing nucleotide sequences of the mitochondrial COI and ND4 genes. Deep-sea mussels were clustered into three groups by basal trichotomous divergence. The first was composed of four species found in Japanese waters and one species from the Gulf of Mexico, which contain methanotrophic endosymbiotic bacteria. The second included nine species distributed in the West and East Pacific, Indian, and Atlantic Oceans. Members of the second group were trichotomously divided into the Indo-West Pacific, Atlantic, and East Pacific subclusters. The Indo-West Pacific subcluster was composed of three very closely related species with mutual genetic distances at the intraspecific level (av. 0.019 in COI and 0.009 in ND4 relative to av. 0.156 in COI and 0.265 in ND4 among Bathymodiolus species other than Cluster A species), suggesting some gene flow among these species. The third consisted of two West Pacific species. Species in the second and third groups contain mainly thioautotrophic endosymbionts, including some species harboring both methanotrophs and thioautotrophs. 相似文献