Search

Aim Freshwater planarians may have a wide geographical range despite their assumed low vagility. Found across four continents, Dugesia may have either an ancient origin on a large palaeo landmass, followed by colonisation in different regions before continental fragmentation, or a more recent origin and subsequent transoceanic dispersal. We seek to resolve between these two hypotheses. Location Africa, Eurasia and Australasia. Taxon Genus Dugesia (Platyhelminthes: Tricladida: Dugesiidae). Methods We used data from the sequencing of six gene fragments and comprehensive taxonomic sampling of Dugesia from across its distribution range to reconstruct the phylogeny of this genus using maximum likelihood and bayesian inference methods. We conducted two phylogenetic dating analyses using Platyhelminthes fossils and palaeogeological events. Basing on the time-calibrated molecular phylogenetic framework we evaluated the contribution of vicariance and dispersal to the biogeographical evolution of Dugesia. By reconstructing the ancestral areas and present-day potential distribution using BioGeoBEARS and niche modelling, we elucidated the biogeographical history of the genus. Results The present-day distribution of Dugesia is a result of different vicariance and dispersal events. However, we also found evidence of transoceanic dispersal. Consistent with previous hypotheses, Dugesia dates to the Upper Jurassic in the Afro-Malagasy Gondwana region. We unveiled a novel biogeographical scenario for the genus, involving multiple events of colonisation in Eurasia from continental Africa via at least three dispersal routes. Main conclusions Dugesia is an ancient genus having reached its present distribution through a complex history of dispersal and vicariant events following its origin in southern Gondwana. Despite the low vagility of Dugesia, we found evidence of their overseas dispersal.

Adult odonate biodiversity was investigated to understand their relationship with pond management practices and environmental conditions in a rapidly urbanized landscape. Twenty-four farm ponds in Taoyuan City were selected and classified into five pond groups based on pond management practices. In total, 21 species, 17 genera, and 6 families of odonates were recorded for a total of 5701 individuals between June 2014 and July 2015. The abundance of Odonata was unrelated to pond size or distance to the nearest pond; however, odonate species richness was negatively and significantly correlated with pond size. Pond management practices considerably affected pond aquatic macrophytes and dike construction materials. Ecology park ponds under intense human management and undisturbed ponds without any human management had higher species richness than did the ponds in the other three fish farming groups. Species richness was highest in small and human-modified ponds. By contrast, species richness was lowest in two fish farming pond groups. These results suggest that pond management practices can increase or reduce odonate species richness depending on the alteration of pond microhabitat features. Our observations suggest that the enhanced habitat quality of small ponds provides an opportunity to protect freshwater biodiversity for local governmental civil servants in urbanized landscapes.

When the first case of coronavirus disease 2019 (COVID-19) infection occurred in China in late 2019, Taiwan was predicted to be one of the most affected countries because of its economic activities and transportation exchanges with China. On January 20, 2020, the activation of Taiwan’s Central Epidemic Command Center (CECC) was established to integrate resource of the administration, the academic, medical and private sectors and formulate guidelines and regulations in the fight against COVID-19. As of February 10, 2021, only less than 1,000 cases of COVID-19 have been confirmed in Taiwan since the first confirmed case on January 21, 2020, and most cases are classified as imported. Tight border controls, rapid mobilization by the public and private sectors, prompt decision-making and implementation, well-coordinated distribution of medical supplies, and transparent information and advanced digital technology are helping Taiwanese society to fight COVID-19. Especially, digital technology provides a new type of social innovation to help making public to easy access transparent information or prevent the transmission of misinformation and disinformation to combat COVID-19 effectively in Taiwanese society.

Hexabromocyclododecane (HBCD) is one of the most frequently used brominated flame retardants (BFRs) in the industries nowadays. Despite being listed as persistent organic pollutant (POP), it is still in use until 2025. Because of its bio-accumulative and toxic characteristics, the applicable remediation approach is required. The aim of this study is to identify the microbial community from soil with HBCD degradation ability. The soil suspension and soil samples from Chiang Chun Soil and River Bank Soil showed to degrade HBCD by 60% 4 days after treatment, the debromination ratio was around 60%, and the total HBCD removal ratio reached 70% and 77.9%, respectively. The HBCD debromination metabolites, and oxidation metabolites were identified by GC–MS. The microbial taxonomic diversity was observed with DGGE approach to evaluate the effect of HBCD of microbial community. Bacillus spp. and Clostridium spp. were identified as the dominant microbes in the Chiang Chun Soil, but the amount of Bacillus spp. were showed to be affected by HBCD. In conclusion, HBCD could be removed by the microbial consortium in soil under aerobic culturing condition by various metabolic pathways.

Owing to their widespread use in wooden products, industrial products, cosmetics, and personal care products, biocides are frequently detected in wastewater and surface water. In this study, I exam...

Although many epidemiological studies have been conducted on Yucheng cohorts, this incident has rarely been examined from social-ecological perspectives. This study adopted a social-ecological model as a framework to provide a more complete description of Yucheng in order to understand its effects on affected individuals, communities, and society. At first, recent studies on Yucheng victim's health effects was updated. Long-term follow-up studies of Yucheng cohort have revealed the adverse health effects exerted on victims and their children. Subsequently, this study uses the disaster ecology model as a conceptual framework to review Yucheng. The movements of Yucheng victims and their supporters have constituted a primary actor for promoting the personal and legal rights of Yucheng victims. Finally, this study discusses how to improve future studies to effectively assist victims in their recovery from this incident.

Regarding the humane use of animals in scientific research, invertebrates are often recommended in toxicological studies. "Freshwater planarians" refers to numerous free-living freshwater members of the Class "Turbellaria" of the phylum Platyhelminthes. This group of invertebrates has received extensive attention from biologists for many years because of their unique biological characteristics, such as the primitive form of the central nervous system and notable capability to regenerate tissues. Using freshwater planarians as test animals in chemical toxicity studies has grown in popularity since the 1960s. Results from various toxicological experiments have collectively suggested that freshwater planarians can serve as not only alternative models for chemical toxicity screenings in laboratories but also as potential bioindicators for the quality of freshwater environments. However, thus far, no standardized battery of tests for conducting toxicological studies that includes freshwater planarians has been proposed. This paper comprehensively reviews the toxicological information obtained from chemically exposed planarians and proposes practical factors for consideration in toxicity experiments with freshwater planarians as test organisms.

In this study, epidemiological studies on the effects of temperature-related and water-related extreme events on health in Taiwan were reviewed. Results of studies on the effects of temperate-related extreme events on health have varied because of the different indices used and diseases targeted; however, overall, these studies suggest that extreme low-temperature events generate greater mortality risk than do extreme high-temperature events, although health consequences from extreme high-temperature events cannot be ignored. With regard to health consequences from water-related extreme events, most related studies have focused on the association between floods and excessive rainfall, caused mainly by typhoons, with morbidity and mortality. Results of numerous studies have suggested that floods and excessive rainfall increase the risk of various diseases, especially water-borne, vector-borne and food-borne diseases.

Bone marrow stromal cells (MSCs) are a useful source of stem cells for the treatment of various brain injury diseases due to their abundant supply and fewer ethical problems compared with transplant treatment. However, the clinical application of MSCs is limited due to allograft rejection and immunosuppression in the process of MSCs transplantation. According to previous studies, microglial cell autophagy occurs following co-culture with MSCs. In the present study, exosomes were obtained from MSCs and subsequently characterized using transmission electron microscopy, atomic force microscopy and dynamic light scattering particle size analysis. The type of microRNAs (miRs) found in the exosomes was then analyzed via gene chip. The results demonstrated that microglial cell autophagy could be induced by exosomes. This mechanism was therefore investigated further via reverse transcription-quantitative PCR, western blotting and luciferase assays. These results demonstrated that exosomes from MSCs could induce microglial cell autophagy through the miR-32-mediated regulation of disabled homolog 2-interacting protein, thus providing a theoretical basis for the clinical application of miRs in MSCs.

Although a freshwater planarian is proposed as a potential model for studying toxicities of environmental pollutants, they are less sensitive to metal exposures, compared to other freshwater invertebrates. We hypothesised that the metal uptake is low in treated planarians, which may lead to their higher tolerance to metals. The acute toxicities of Cu and Zn to Dugesia japonica were determined. The 24- and 48-h median lethal concentrations were 4.50 and 3.46 mg L−1, respectively, for Cu, and 41.97 and 37.79 mg L−1, respectively, for Zn. Accordingly, combining with the data on Cd in our previous study, higher tolerance of planarians to metals was revealed. Also, tissue levels of Cd, Cu, and Zn in treated D. japonica were determined, and their dissolved uptake rate constants (k1) were calculated. Results showed that bioaccumulations of these metals in D. japonica were, indeed, lower than that in other freshwater invertebrates having higher susceptibilities to these metals.

Using specific neurobehaviors as endpoints, previous studies suggested that planarian neurotransmission systems could be targets of Cd neurotoxicity. However, direct evidence for disturbed neurotransmission systems by Cd in treated planarians is still lacking. In planarians, dopamine (DA) and serotonin (5-HT) play critical roles in neuromuscular function, but little is known about their metabolic degradation. Therefore, in this study, we attempted to determine the appearances of DA, 5-HT, and their metabolic products in the freshwater planarian Dugesia japonica, characterize the activity of enzymes involved in their metabolism, and investigate the effects of Cd on planarian 5-HTergic and DAergic neurotransmission systems. Only DA, 5-HT, and 5-hydroxyindole-3-acetic acid (5-HIAA) were found in planarian tissues. Further enzymatic study revealed the activity of planarian monoamine oxidase (MAO) but not catechol-O-methyl transferase (COMT). These findings suggest that planarian MAO catalyzes the metabolism of 5-HT into 5-HIAA. However, DA metabolites from the MAO-involved metabolic pathway were not found, which might be due to a lack of COMT activity. Finally, in Cd-treated planarians, tissue levels of 5-HT and DA were decreased and MAO activity altered, suggesting that planarian neurotransmission systems are disturbed following Cd treatment.

Regeneration is a vital physiological process for survival of adult organisms. Bisphenol A (BPA), diethystilbestrol (DES), 17α-ethinylestradiol (EE2), and 17β-estradiol (E2) were examined for their effects on head formation in decapitated freshwater planarians (Dugesia japonica). The median lethal concentration of the test chemicals and the median inhibitory concentration for decapitated planarians and different regenerative endpoints, were determined for 3–7 d of exposure. For planarian head regeneration, the no-observed-effect level of BPA and DES was 0.05 mg L−1 and 1 mg L−1 for EE2 and E2. The effects of BPA, DES, and EE2 on asexual planarian regeneration did not correspond with the order of their estrogenic potencies, suggesting that the effects, at least partially, were due to general toxicity rather than their estrogenicity. In view of the published data on concentrations of xenoestrogens in water bodies versus the nominal levels tested here, this study suggests that the current environmental level...

The interactions among climate change, air pollution, and human health are multiple and complex. Many epidemiological studies in Taiwan have consistently demonstrated the effects of short-term exposures to extreme weather events, particulate matter, and traffic-related air pollutants on a variety of health effects. However, these findings might not explain or predict overall seasonal mortality patterns to provide insights into the drivers of mortality acting on society levels for public health policy and practice. There are very limited studies on seasonality of weather, air pollution, and mortality in Taiwan. The objectives of this study are to evaluate if there are any changes in trends and seasonality of mortality in three major Taiwanese cities from 1991 to 2010 and examine its association with climatic condition and air pollution. Among these major Taiwanese cities, seasonal mortality patterns are similar in two subtropical cities, Taipei and Taichung, compared to another tropical city, Kaohsiung. Taipei had significantly increased trends in most monthly temperature variables and the number of hot days examined during 1991–2010 compared to the other two cities. Winter/summer ratios of mortality only showed a decreased trend in Taipei, but not in Taichung or Kaohsiung. Mean monthly ambient temperature was also found as the most optimal temperature variable for predicting all-cause monthly mortality at all three cities in this study. Seasonal mortality patterns in three cities were with higher levels of deaths from December to March. Trends in air quality are showing mixed patterns over the past two decades. SO2, CO, and NOx concentrations have decreased significantly and steadily, while O3 has significantly increased in recent years. In three major Taiwanese cities, O3 and PM10 are major air pollutants of current concerns. The results of this study showed that monthly mean O3, PM10, and NOx levels and monthly mortality were not closely related, but temperature-related variables were positively associated with monthly mortality among three major Taiwanese cities. Moreover, changes in other socioeconomic and demographic factors may also play a key role in determining seasonality mortality and morbidity and need to be considered in future studies.

Biomaterials are commonly used in vitro or in vivo. Synthetic vascular prostheses, artificial bones, and artificial joints are used in vitro. Bone scaffolds demand components with good biocompatibility, mechanical strengths, and pore size. This allows the bone tissue to attach to and grow inside the bone scaffolds. Polyethylene terephthalate (PET) filaments and chitosan have good biocompatibility and are non-toxic. This study prepares biocompatible, porous, 1- and 2-layer three-dimensional PET/chitosan tubular knits by a freeze-drying method. PET plied yarns with three combinations of various denier (D) and coefficients of twist-150D/2, 225D/4, and 300D/3-are knitted into tubular knits with proper mechanical properties and porous structure. The resulting tubular knits are then alkali treated with 3 M sodium hydroxide (NaOH) reagent for 90 min, immersed in 1 wt% chitosan solution, and then freeze-dried, forming the porous PET/chitosan tubular knits. The functional group analysis and degradation of the alkali-treated chitosan films are first evaluated, and then the tensile strength, surface observation, pore size, and biocompatibility of the resulting PET/chitosan tubular knits are evaluated. The experimental result shows that 1- and 2-layer PET/chitosan tubular knits have desirable mechanical strength, stability, and biocompatibility antibacterial properties.

Pharmaceutically active compounds are produced worldwide and consumed in large quantities, so these chemicals are frequently detected in limnic environments posing potential ecological risks. Thirty pharmaceutically active compounds were selected for examination of their acute toxicity for freshwater planarians (Dugesia japonica). Among the 30 compounds tested, diclofenac, mefenamic acid, naproxen, propranolol HCl, and diphenhydramine HCl had a 48-h nominal LC50 below10 mg L−1, and for 18 chemicals, it exceeded 100 mg L−1. The 96-h nominal LC50 was below 10 mg L−1 for diclofenac, mefenamic acid, naproxen, propranolol HCl, diltiazem HCl, diphenhydramine HCl, hydroxyzine HCl, and triprolidine HCl, and for 15 chemicals, it exceeded 100 mg L−1. Among different therapeutic groups, analgesics were most toxic to planarians, and antibiotics were least toxic. Antihistamines and beta blockers varied in their acute toxicity to planarians. At the current environmental levels, none of the tested pharmaceutically activ...

Many chemicals commonly occurring in surface water are found to be hormonally active. Fourteen compounds including four sex hormones, three synthetic hormones, one non-steroidal anti-androgen, and six industrial endocrine-disrupting chemicals were selected to examine their acute toxicities on the freshwater planarian, Dugesia japonica. Among all test chemicals, diethylstilbestrol had the highest toxicity. Relatively, the toxicities of the synthetic hormones were higher than the natural ones. Among the six industrial endocrine-disrupting chemicals tested, bisphenol A was the most toxic, with a 48-h LC50 of 8.3 mg L−1. Overall, the natural or synthetic hormones, other than estrone and estriol, were more acutely toxic to planarians than the industrial endocrine disruptors tested. The acute toxicities of the test chemicals to Dugesia japonica were in the same order of magnitude as those to Daphnia magna based on available published data. Despite this study used non-environmentally relevant levels, such kinds ...

Internal transcript spacer 2 (ITS2) is one of the broadly used standard core barcodes and also the only nuclear barcode in identification of Chinese traditional medicine. Although the DNA barcode method based on ITS2 is popular and has been used in Chinese Pharmacopoeia, its low discriminatory efficiency is still a problem to its extensive application. Therefore, further study is still necessary to explore its phylogenetic information for medicinal plants identification. In cells, ITS2 activity is based on its secondary structure. The secondary structures are particularly useful in phylogenetic analysis because they include information not found in the primary sequence. In this study ITS2 secondary structure of 40 samples from 26 species were predicted and used to explore their utility in addressing the identification problems of Chinese traditional medicine in Solanum. The secondary structures were predicted and aligned, and their consensus models were generated using the three different software of LocARNA, MASTR and PicXAA-R. RNAstat software was used to transform the secondary structures into 28 symbol code data for maximum parsimony (MP) analysis. The results showed that the phylogenetic information increased 88.57% after ITS2 secondary structure information has been added, and then the support values above 50%, 75% and 90% in the tree increased 19.05%, 66.67% and 66.67%, respectively, indicating that the identification of Solanum medical plants has been well resolved. Thus, our analysis suggests that ITS2 secondary structure information should be incorporated into the current DNA barcoding analysis as a beneficial supplement of phylogenetic information.

Having good mechanical strength, biocompatibility, and workability, polyethylene terephthalate (PET) is often used as a biomaterial. In this study, PET filaments with various deniers are made into plied yarn with various coefficients of twist. The plied yarn is then made into PET knitted fabrics. Mechanical property tests are performed to determine the differences among the various PET knitted fabrics. Finally, by using cell culture, the PET knitted fabrics are analyzed and evaluated with their cell attachment.

Although toxic responses of freshwater planarians after exposure to environmental toxicants can be observed through external toxicological end points, physiological responses inside the bodies of treated planarians have rarely been investigated. The present study was designed, using cadmium (Cd) as a reference toxicant, to determine its bioaccumulation and toxicodynamics in the freshwater planarian, Dugesia japonica, after acute toxicity was obtained. Accumulated Cd concentrations, metallothionein levels, and the oxidative status in planarians were determined after exposure to Cd. Furthermore, we hypothesized that the acute death of Cd-treated planarians was associated with increased oxidative stress. After Cd-treated planarians were coexposed to antioxidant, N-acetylcysteine (NAC), we found that NAC protected planarians from Cd lethality by maintaining the oxidative status and decreasing the bioaccumulation of Cd. The results of the present study support planarians being used as a practical model for toxicological studies of environmental contaminants in the future.

Fourteen benzophenone-type UV filters and four paraben preservatives were selected to examine their acute toxicities on Dugesia japonica. The 48-h LC50 values for planarians exposed to benzophenone-type UV filters can be ranked as oxybenzone > mexenone > 5-chloro-2-hydroxybenzophenone > 2,4-dihydroxybenzophenone > 2-hydroxybenzophenone > dioxybenzone > benzophenone > 2,2′,4,4′-tetrahydroxybenzophenone > 4-hydroxybenzophenone > 3-hydroxybenzophenone > 4,4′-dihydroxybenzophenone > 2,2′-dihydroxy-4,4′-dimethoxybenzophenone > 2,3,4-trihydroxybenzophenone > sulisobenzone with a range from 0.9 to 145 mg L−1 with a similar sequence for the 96 h LC50 values, ranging from 0.5 to 77 mg L−1. The 48 and 96 LC50 values for planarians exposed to paraben preservatives can be ranked as butylparaben > propylparaben > ethylparaben > methylparaben. Among all the tested chemicals, oxybenzone was the most toxic and sulisobenzone the least toxic chemical to planarian at each exposure period. Most benzophenone-type UV filters a...

Aims. To investigate why patients do not choose percutaneous endoscopic gastrostomy or percutaneous endoscopic jejunostomy as a route for long-term feeding. Background. Home enteral tube feeding is well recognised as a valuable therapeutic option for patients requiring nutritional support following discharge from hospital. The number of patients discharged from hospital and receiving home enteral tube feeding increases annually in Taiwan. Design. A cross-sectional study. Method. Participants (n = 607) were chosen from one free-standing home care agency and three hospital-based home care departments in Taipei. A review of the patients’ records to gather demographic data, medical diagnosis, length of home care and length of intubation prior to the home visit was conducted. A face-to-face interview was conducted at the time of the home visit. Findings. The prevalence rate of home enteral tube feeding was 70·3% (n = 427). Of the 427 tube-fed subjects, 93·4% were fed with a nasogastric tube. The most common reasons for refusing to use percutaneous endoscopic gastrostomy or percutaneous endoscopic jejunostomy were ‘too old to suffer from an operation’, ‘worried about wound infection or leakage after performing percutaneous endoscopic gastrostomy’ and ‘to keep subjects’ body integrity’. Stroke, no dementia, poor activities of daily living and poor cognitive status were significant predictors of being tube-fed, while higher education and better cognitive status were significant predictors of percutaneous endoscopic gastrostomy or percutaneous endoscopic jejunostomy use. Conclusion. The reasons patients refused to use percutaneous endoscopic gastrostomy or percutaneous endoscopic jejunostomy reflect the influence of cultural values and the level of patients’ education, which home health care nurses need to discuss with patients in detail. Relevance to clinical practice. Investigating patients’ perspective on the meaning of ‘body’ in Taiwanese culture and the decision-making processes related to home enteral tube feeding is recommended for nurses to provide better care and support when home enteral tube feeding in an option.

Perfluorinated compounds are widespread in the environment, animals, and humans, and have been proposed to be included in the list of persistent organic pollutants that have the potential to cause a global pollution problem similar to that caused by existing persistent organic pollutants. Daphnia magna was used to evaluate the chronic effects of the ammonium salt of pentadecafluorooctanoic acid (PFOA) and the potassium salt of perfluorooctane sulfonate (PFOS) on the reproduction and biochemical responses of aquatic animals. Reproduction of Daphnia magna was a more sensitive response than survival or enzyme activities in daphnia exposed to PFOA or PFOS. No observed effect concentrations (NOECs) of daphnia reproduction were 1 and 10mg/l after 21days of exposure to PFOA and PFOS, respectively. The median lethal concentration (LC50 )a nd survival NOEC values of PFOA for Daphnia magna were all greater than 100mg/l after 21days of exposure. The LC50 and survival NOEC values of PFOS were 9.1mg/l and 5mg/l after 21days exposure. No significant changes in cholinesterase, catalase and heme peroxidase activities were observed between controls and exposure to PFOA or PFOS. This suggests that these enzyme activities are not sensitive biomarkers of exposure to these two chemicals or their effects in daphnids after chronic treatment. Based on the results of this study and other findings published in the literature, it is suggested that current PFOS and PFOA levels in freshwater may have no harmful im

One closed uncontrolled landfill, the Neihu garbage dump, and one active controlled landfill, the Sanzhuku sanitary landfill, were selected for investigation of their leachate characteristics and effects on adjacent river water quality before and after rainfall in northern Taiwan. A total of seven samplings were made during February and June 2007, with four samplings done after individual rainfall events on study sites. Water quality of runoff samples collected from the Sanzhuku sanitary landfill showed less pollution than the water quality of leachates collected from the Neihu garbage dump; however, some water quality levels of leachate samples collected from the Neihu garbage dump were relatively high, such as ammonia nitrogen (NH3-N), orthophosphate (PO43-) and biochemical oxygen demand (BOD5). At the uncontrolled dump, rainfall lead to dilution effects on river water NH3-N and PO43- concentrations, but not other water quality parameters. In contrast, the concentrations of bisphenol A (BPA) and nonylphenol were increased in both types of landfills after rainfall in the present study. Dilution effects of rainfall on most water quality parameters and toxicity tests were observed in the Neihu garbage dump leachates after rainfall, but not for the Sanzhuku Landfill runoff. The highest concentration of BPA measured in this study was 25.8 μg L-1 in the Sanzhuku sanitary landfill runoff after the heaviest rainfall event, during which 236 mm of rainfall accumulated over four days. The results of this study suggest that both uncontrolled and controlled landfill leachates can be an important potential pollution source of BPA to adjacent water bodies.

Compared to the estrogenic effects of 4-nonylphenol (NP), there is little data available on other potential toxic effects of NP in aquatic animals. The effects of NP on cholinesterase (ChE) and carboxylesterase (CbE) activities of male guppies exposed to 10, 60, 150, or 300 μg L−1 NP were examined after 1, 2, 4, and 7 days of treatment. A significant muscle ChE inhibition, that used acetylthiocholine iodide as a substrate, was noted in male guppies in all NP treatment groups after a 4-day exposure, and 60 and 150 μg L−1 of NP treatment groups after a 7-day exposure. All guppies exposed to 300 μg L−1 NP died during the 7-day treatment. However, there was no significant inhibition of muscle ChE that used butyrylthiocholine iodide as a substrate in male guppies for any NP treatments in different exposure times. There were no CbE activity differences in livers of male guppies among NP treatment groups after different exposure times. This is the first report showing the ChE activity inhibition by NP in fish. Further mechanistic studies are needed to define how NP directly or indirectly alters ChE activities at molecular level. The implication of ChE inhibition of NP on potential impacts of aquatic animals also warrants further research.

Decabrominated diphenyl ether (PBDE 209) is the second most used brominated flame retardant (BFRs). Many studies have shown that some of the BFRs act as endocrine disruptors via alterations in thyroid hormone homeostasis and affect development. Little is known about the effect of prenatal exposure to PBDE 209 on the development in male offspring. Using a CD-1 mouse model, we attempt to estimate the possible effect of in utero exposure to PBDE 209 on thyroid hormone and hepatic enzymes activities in male offspring. Pregnant mice were administered different doses of PBDE 209 (10, 500, and 1500 mg/kg/day) or corn oil for controls per gavage from gestational days 0-17. In adult male offspring whose mothers had been treated with 1500 mg/kg of PBD 209, hepatic enzyme activity of S9 7-ethoxyresorufin O-deethylase (EROD) was weak but significantly increased (54%). However, no significant changes were observed in S9 4-nitrophenol uridinediphosphate-glucuronosyltransferase (UDPGT) in any of the treatment groups. Serum triiodothyronine (T3) was found to have decreased significantly (ca. 21% both 10 mg/kg and 1500 mg/kg) in offspring, but not thyroxine (T4). Histopathological examination revealed that prenatal exposure of PBDE 209 might be related with cell swelling of hepatocytes in male offspring and there were mild changes in the thyroid glands in 1500 mg/kg group. These data demonstrate that PBDE 209 is likely an endocrine disrupter in male mice following exposure during development. Further studies using environmentally relevant doses are needed for hazard identification.

Effects of climate change on human health become increasingly a growing concern. Especially, the worldwide risk of vector-borne diseases, such as dengue fever, could be strongly influenced by meteorological conditions. Taiwan is unique in terms of its geographical location and abundant ecological environments. It makes Taiwan an unusual epidemic region for dengue disease. This chapter focuses on risk factors related to climate change and geographical characteristics which have been shown to affect dengue transmission in Taiwan. Empirical studies all concluded that relationship between temperature and dengue incidence is highly correlated. Some of studies also concluded that temperature increase has more dramatic influence to dengue incidences in southern Taiwan. However, the effects of other meteorological factors, including precipitation and humidity, on dengue incidence are rather inconsistent. Extreme weather events, such as heavy rainfall, would be possible to damage the habitats of Aedes mosquitoes and also beneficial to construct them with lag time of several weeks. The role of extreme weather events in dengue transmission needs to be further investigated. Further studies should also put more focus on the extent of influence of meteorological conditions on human activities and what activity changes may increase or decrease the risk of dengue transmission.

The development of a high-throughput tool is required for screening of environmental pollutants and assessing their impacts on aquatic animals. Freshwater planarians can be used in rapid and sensitive toxicity bioassays. Planarians are known for their remarkable regeneration ability but much less known for their metabolic and xenobiotic biotransformation abilities. In this study, the activities of different phase I and II enzymes were determined in vivo by directly measuring fluorescent enzyme substrate disappearance or fluorescent enzyme metabolite production in planarian culture media. For phase I enzyme activity, O-deethylation activities with alkoxyresorufin could not be detected in planarian culture media. By contrast, O-deethylation activities with alkoxycoumarin were detected in planarian culture media. Increases in 7-ethoxycoumarin O-deethylase (ECOD) activities was only observed in planarians exposed to 1μM, but not 10μM, β-naphthoflavone for 24h. ECOD activity was inhibited in planarians exposed to 10 and 100μM rifampicin or carbamazepine for 24h. For phase II enzyme activity, DT-diaphorase, arylsulfatases, uridine 5'-diphospho (UDP)-glucuronosyltransferase or catechol-O-methyltransferase activity was determined in culture media containing planarians. The results of this study indicate that freshwater planarians are a promising model organism to monitor exposure to environmental pollutants or assess their impacts through the in vivo measurement of phase I and II enzyme activities.

2,2',3,3',4,4',5,5',6,6'-Decabrominated diphenyl ether (PBDE 209) is the second most used brominated flame retardant (BFRs) in constructed materials because it is considered less toxic than others, though other fire retardants, some congeners of PBDE 209, are reported to be toxic. This combined the fact that PBDE 209 has been found in high levels in human milk, blood, indoor environments as well as in foodstuffs has led us in this study attempt to find out whether PBDE 209, also known as decaBDE and decabrominated diphenyl oxide (DBDPO), has an adverse effect on this histology of testes and sperm in CD-1 male mice. The mice we studied were divided into groups and gavaged with 10, 100, 500 and 1500 mg/kg PBDE 209 in corn oil per day between postnatal Days 21 and 70. On Day 71, the mice were anesthetized and sperm function, testis DNA content, and histopathology were studied. We found in the 500- and 1500-mg/kg/day groups that neonatal exposure to PBDE 209 reduced sperm epididymal sperm mitochondrial membrane potential (MMP), reduced amplitude of the lateral head displacement (ALH) and induced the generation of hydrogen peroxide (H2O2) in the sperm of sexually mature male mice, without affecting the sperm count, motility, morphology, curvilinear velocity (VCL), angular progressive velocity (VAP), straight-line velocity (VSL), beat-cross frequency (BCF), sperm chromatin structure assay (SCSA), superoxide anion (O2-*) generation, DNA content in testis cells, or testicular histopathology. ALH was positively associated with an increase in MMP and negatively associated with generation of sperm H2O2. The reduction of MMP was negatively associated with an increase in generation of sperm H2O2. The presence of the relationships between sperm ALH, MMP, and generation of H2O2 indicate toxic action possibly resulting from PBDE 209-induced oxidative stress. In conclusion, this is the first study to report the lowest-observed-adverse-effect level (LOAEL) for sperm function to be 500 mg/kg of PBDE 209 in male mice. Decreased epididymal sperm MMP and ALH as well as induced generation of sperm H2O2 were some of the most serious effects of postnatal PBDE 209 exposure. Future investigations should be performed to study the effects of prenatal exposure of PBDE 209 and the mechanism behind PBDE 209-related oxidative stress in the fetal and pubertal stages of development.

Adult male guppies (Poecilia reticulata) were exposed to 4-nonylphenol (NP) at nominal concentrations of 10, 60, and 150 μg/L for 7, 14, or 21 days. Significant induction of vitellogenin (VTG) was found in male guppies exposed to 1 μg/L of 17β-estradiol and 60 or 150 μg/L of NP after 7, 14, or 21 days. Maximum induction was seen after 14 days of treatment at these concentrations. On the other hand, significant induction of VTG in male guppies exposed to 10 μg/L of NP was observed only after 21 days of treatment. A time-dependent tendency of reduction of the gonadosomatic index (GSI) in male guppies treated with 17β-estradiol or NP was observed, but no corresponding concentration-dependent tendency was detected. There were also no differences in the liver somatic index (LSI) of male fish treated with various concentrations of NP during the above-mentioned exposure periods. Preliminary data presented in this study strongly suggests that measurement of plasma VTG induction in male guppies is a suitable and rather sensitive indicator of exposure to estrogenic chemicals. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 53–59, 2005.

Polychlorinated biphenyls (PCBs) are considered potential endocrine disruptors due to their ability to act as estrogens, antiestrogens and goitrogens. The aim of this study is to ascertain whether acute postnatal treatment with 3,3 ′ ,4,4 ′ -tetrachlorobiphenyl (CB 77) affects sperm function and hormone levels in adult rats. Male Sprague–Dawley rats received CB 77 by ip injection of 2 or 20 mg/kg at day 21 and sacrificed at day 112. At day 112, right and left testis weights were significantly increased, whereas sperm count, motility, total motile sperm count, curvilinear velocity, average path velocity, straight-line velocity, and beat-cross frequency for motile sperm were significantly decreased in rats treated with 20 mg/kg CB 77. Sperm–oocyte penetration rate was significantly reduced in rats treated with either 2 or 20 mg/kg CB 77. There was high sperm acrosome reaction rate (ARR) in the 20 mg/kg CB 77-treated rats. There was a significant increase in thyroid-stimulating hormone level in the 20 mg/kg CB 77 group. However, no changes were seen in serum testosterone, thyroid hormones, or prolactin concentrations at day 112. In summary, this study showed that postnatal exposure to CB 77 might affect spermatogenesis, motility, ARR, and ability of fertilizing oocytes in mature rats. These results suggest that the sperm functions may be more susceptible or adapt less readily than the thyroid functions to endocrine disruption caused by dioxin-like PCB congeners.

Urban air pollution is a serious problem in both developing and developed countries, and antioxidant enzyme activities in plants have been suggested as a useful bioindicator of air pollution. In this study, the seasonal and spatial variability of peroxidase and superoxide dismutase activities were measured in leaves of Ficus microcarpa at eight sampling sites in the Taipei metropolitan area and one background site in rural area at each month for a year. The spatial pattern of peroxidase activity in figs collected from the Taipei metropolitan area was similar to the spatial pattern of O3 concentration in the Taipei metropolitan area. The peroxidase activities of Ficus microcarpa were significantly higher at sampling sites from the outer zone of the metropolitan area than those from the inner zone of the metropolitan area in spring and summer. On the other hand, the spatial pattern of superoxide dismutase activity in fig leaves did not show significant differences between the inner and outer zones of the Taipei metropolitan area. In addition, peroxidase activities, but not superoxide dismutase activities, of Ficus microcarpa were significantly higher in sites with high traffic density than those in low traffic density sites. Even though peroxidase activities in Ficus microcarpa tended to be higher in high traffic density sites or some sites with high ozone concentration, site-specific changes of peroxidase activity in Ficus microcarpa due to O3 pollution were not clearly observed in this study. Based on these results, neither peroxidase nor superoxide dismutase in Ficus microcarpa is a sensitive bioindicator for O3 pollution, although peroxidase shows some potential to be used as a general bioindicator of air quality.

Pain relief medications commonly occur in the aquatic environment at measurable levels. While the neurotoxicity of pain relievers to higher vertebrates is currently known, little is known about their effects on aquatic animals. This study investigated the neurotoxicity of pain relievers to aquatic animals. We used three neurological enzymes, cholinesterase (ChE), adenosine triphosphatase (ATPase), and monoamine oxidase (MAO), from a freshwater planarian (Dugesia japonica) and green neon shrimp (Neocaridina denticulata) as biomarkers to examine the effects of pain relievers on in vitro activity. The activity of MAO and ChE, but not ATPase, was significantly inhibited by acetaminophen, but not by other pain relievers examined. It was likely that the inhibitory effects of acetaminophen on shrimp neurological enzymes were more severe than on the planarian. These findings suggest that acetaminophen is potentially neurotoxic to aquatic animals, at least in terms of neurotransmission disturbance.

Polychlorinated biphenyls (PCBs) with the liable 2,3,6-substitution are important components of certain commercial mixtures and frequently detected in biota, but little is known about their enzyme induction abilities and possible endocrine-disrupting effects. CB 132 (2,2',3,3',4,6'-hexachlorophenyl) and CB 149 (2,2'3,4',5',6-hexachlorophenyl) were investigated in weanling female rats dosed intraperitoneally on days 21 and 22 and killed on day 24 of age. Uterotropic response, serum thyroid hormone, and hepatic enzyme induction were examined in prepubertal female rats treated with these two environmentally relevant 2,3,6-substituted chlorobiphenyl (CB) congeners from 8 mg/kg to 96 mg/kg. The readily metabolized CB 132 did not cause any significant increase in all endpoints measured in the present study. On the other hand, CB 149 was a weak PROD and BROD inducer and a modest depleter of serum thyroxine in prepubertal female rats. The finding of thyroid hormone disruption by CB 149 may lead to biologically significant neurobehavioral and neurochemical changes in developing animals via milk lactation.

Polychlorinated biphenyls (PCBs) with the labile 2,3,6-substitution are important components of atmospheric and certain food chain exposures, but little is known about their biological activities. Chlorobiphenyl 110 (2,3,3',4',6-pentaCB) was investigated in weanling female rats dosed ip on days 21 and 22 and killed on day 23 of age. The initial preparation of CB 110 markedly induced 7-ethoxyresorufin O-dealkylase (EROD) activity and was found to be contaminated with coplanar 3,3',4,4',5-pentaCB (CB 126). The contaminated preparation (CB 110C) was purified with activated charcoal (CB 110P). The CB 110P induced pentoxyresorufin O-dealkylase (PROD), was weakly uterotropic and a modest depleter of serum thyroxine (T4). CB 110C caused increased liver weight, induced EROD, PROD, and UDP glucuronyl transferase activities and caused a greater depletion of serum T4; on the other hand, it suppressed the PROD induction and the uterotropic effect of CB 110P. Hepatic residues of CB 110 were a constant 2-3% of the dose while those of CB 126 (from CB 110C) increased with increasing dose to as much as 50% of the dose.

Although freshwater planarians are evolutionarily primitive, they are some of the simplest bilateral animals possessing integrated neural networks similar to those in vertebrates. We attempted to develop planarian Dugesia japonica as a model for investigating the neurotoxicity of environmental pollutants such as cadmium (Cd). This study was therefore designed to study the effects of Cd on the locomotor activity, neurobehavior, and neurological enzymes of D. japonica. After planarians were exposed to Cd at high concentrations, altered neurobehavior was observed that exhibited concentration-dependent patterns. Morphological alterations in Cd-treated planarians included irregular shape, body elongation, screw-like hyperkinesia, and bridge-like position. To study the direct effects of Cd on neurological enzymes, tissue homogenates of planarians were incubated in vitro with Cd before their activity was measured. Results showed that acetylcholinesterase (AChE), adenosine triphosphatase (ATPase), and monoamine oxidase A (MAO-A) activities were inhibited in a concentration-dependent manner. MAO-B activity was significantly induced by Cd at low concentrations and inhibited at high concentrations. Changes in the in vivo activity of AChE and ATPase were also found after planarians were treated with Cd at a sublethal concentration (5.56 μM). These observations indicate that neurotransmission systems in planarians are disturbed after Cd exposure.

An extract of landfill soil containing high levels of polychlorinated biphenyls (PCBs) was refined by alumina–charcoal column chromatography to remove coplanar PCBs and high relative levels of PCDFs. Both extracts were administered ip in corn oil to immature female rats on Days 21 and 22 of age. Rats were terminated on Day 23 and organ weights, enzyme activities, and serum thyroxine (T4) were measured. The change in characteristics caused by charcoal-stripping was confirmed by comparing hepatic microsomal 7-ethoxyresorufin O -deethylase (EROD), 7-pentoxyresorufin O -depentylase (PROD), 7-benzyloxyresorufin O -dearylase (BROD), and UDP glucuronyl transferase (UDPGT) activities. EROD and 4-nitrophenol (4-NP) UDPGT activities, estimates of aryl hydrocarbon ( Ah ) receptor agonists present, peaked at 140 mg/kg soil extract, declining at 210 mg/kg; these activities in rats treated with the charcoal-refined soil extract were not induced at low doses, but increased linearly from 70 to 210 mg/kg. Conversely, PROD and BROD activities were modestly induced at 7 to 70 mg/kg of either soil extract; however, at higher doses induction was threefold higher in rats receiving the charcoal-filtered extract. Liver weights increased in a pattern similar to EROD induction. At all doses, the weak uterotropic response was greater in rats receiving the charcoal-filtered extract, probably due to removal of antiestrogenic Ah receptor agonists by the charcoal. Serum total T4 declined similarly in rats receiving either extract to about 40% of control values at the highest doses. Short-term integrated bioassays such as this are useful in detecting multiple complex interactions and can be used to define the net effects of mixtures with changing compositions for improved risk assessment..

Air, subsurface soil, and superficial dust from a National Priorities List landfill located in southern Illinois were sampled to determine their potential toxicities. The major components of these landfill extracts were polychlorinated biphenyls (PCBs), with significant amounts of polychlorinated dibenzofurans (PCDFs) and small amounts of polychlorinated dibenzodioxins (PCDDs). The 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalency factor approach has been proposed to estimate the toxic potency of complex mixtures of chlorinated aromatics for environmental risk assessment. However, most components of environmental residues are nonplanar and do not act as aryl hydrocarbon (Ah) receptor agonists, so there is a great risk of not identifying adverse responses that are not dioxinlike. We used a 2-day prepubertal female rat bioassay to examine multiple biological responses, including both dioxinlike and nondioxinlike effects from these landfill extracts. As expected, both types of effects were detected. The soil and dust extracts produced similar dose-response relationships for 7-ethoxyresorufin O-deethylase, 7-pentoxyresorufin O-depentylase, 7-benzyloxyresorufin O-debenzylase, and 4-nitrophenol UDP-glucuronyltransferase induction; the dose response for the air extract deviated from the other two extracts. Soil, dust, and air extracts effectively reduced serum total thyroxine (T4) with similar dose-response relationships, despite the significantly different TCDD toxic equivalent (TEQ) values of these three extracts. Both soil (346 mg PCB/kg) and air (175 mg PCB/kg) extracts caused a greater than 30% increase in uterine wet weight. This study suggests that a more comprehensive approach is required to improve current risk assessment of environmental mixtures. TCDD TEQs reflect only a portion of effects and may especially underpredict effects on T4. Images p712-a Figure 1. A Figure 1. B Figure 1. C Figure 2. A Figure 2. B Figure 3. A Figure 3. B Figure 4. A Figure 4. B