Organohalogen contaminants in wildlife from the Yangtze River Delta : Development of methods and assessments of legacy and emerging persistent organic pollutants

Rapid economic development has occurred during the past few decades in China with the Yangtze River Delta (YRD) area as one of the most progressive areas. The urbanization, industrialization, agricultural and aquaculture activities result in extensive production and application of chemicals. Organohalogen contaminants (OHCs) have been widely used as i.e. pesticides, flame retardants and plasticizers. They are persistent, bioaccumulative and pose a potential threat to ecosystem and human health. However, limited research has been conducted in the YRD with respect to chemicals environmental exposure. The main objective of this thesis is to investigate the contamination level, distribution pattern and sources of OHCs in the YRD. Wildlife from different habitats are used to indicate the environmental pollution situation, and evaluate selected matrices for use in long term biomonitoring to determine the environmental stress the contamination may cause. In addition, a method is developed for dicofol analysis. Moreover, a specific effort is made to introduce statistic power analysis to assist in optimal sampling design. The thesis results show extensive contamination of OHCs in wildlife in the YRD. The occurrences of high concentrations of chlorinated paraffins (CPs) are reported in wildlife, in particular in terrestrial species, (i.e. short-tailed mamushi snake and peregrine falcon). Impurities and byproducts of pentachlorophenol products, i.e. polychlorinated diphenyl ethers (PCDEs) and hydroxylated polychlorinated diphenyl ethers (OH-PCDEs) are identified and reported for the first time in eggs from black-crowned night heron and whiskered tern. High concentrations of octachlorodibenzo-p-dioxin (OCDD) are determined in these samples. The toxic equivalents (TEQs) of polychlorinated dibenzo-p-dioxin (PCDDs) and polychlorinated dibenzofurans (PCDFs) are at mean levels of 300 and 520 pg TEQ g-1lw (WHO2005 TEQ) in eggs from the two bird species, respectively. This is two orders of magnitude higher than European Union (EU) regulation limit in chicken eggs. Also, a novel pattern of polychlorinated biphenyls (PCBs) with octa- to decaCBs, contributing to as much as 20% of total PCBs therein, are reported in birds. The legacy POPs shows a common characteristic with relatively high level of organochlorine pesticides (i.e. DDT, hexacyclohexanes (HCHs) and Mirex), indicating historic applications. In contrast, rather low concentrations are shown of industrial chemicals such as PCBs and polybrominated diphenyl ethers (PBDEs). A refined and improved analytical method is developed to separate dicofol from its major decomposition compound, 4,4’-dichlorobenzophenone. Hence dicofol is possible to assess as such. Statistic power analysis demonstrates that sampling of sedentary species should be consistently spread over a larger area to monitor temporal trends of contaminants in a robust manner. The results presented in this thesis show high CPs and OCDD concentrations in wildlife. The levels and patterns of OHCs in YRD differ from other well studied areas of the world. This is likely due to the extensive production and use of chemicals in the YRD. The results strongly signal the need of research biomonitoring programs that meet the current situation of the YRD. Such programs will contribute to the management of chemicals and environment in YRD, with the potential to grow into the human health sector, and to expand to China as a whole.

Raf kinase inhibitor protein RKIP enhances signaling by glycogen synthase kinase-3β

Raf kinase inhibitory protein (RKIP) is a physiologic inhibitor of c-RAF kinase and nuclear factor ?B signaling that represses tumor invasion and metastasis. Glycogen synthase kinase-3ß (GSK3ß) suppresses tumor progression by downregulating multiple oncogenic pathways including Wnt signaling and cyclin D1 activation. Here, we show that RKIP binds GSK3 proteins and maintains GSK3ß protein levels and its active form. Depletion of RKIP augments oxidative stress-mediated activation of the p38 mitogen activated protein kinase, which, in turn, inactivates GSK3ß by phosphorylating it at the inhibitory T390 residue. This pathway de-represses GSK3ß inhibition of oncogenic substrates causing stabilization of cyclin D, which induces cell-cycle progression and ß-catenin, SNAIL, and SLUG, which promote epithelial to mesenchymal transition. RKIP levels in human colorectal cancer positively correlate with GSK3ß expression. These findings reveal the RKIP/GSK3 axis as both a potential therapeutic target and a prognosis-based predictor of cancer progression.

Refractive errors associated with tilted optic discs:a prospective study

Purpose: Tilted disc syndrome has been described to be associated with obliquely directed long axis of the disc, oblique direction of vessels, retinal pigment epithelial conus, hypoplasia of retina, visual field defects and myopic astigmatism. This prospective study looks at corneal astigmatism in eyes with a tilted optic disc. Refractive errors in these eyes were also analyzed. Methods: Patients with tilted optic discs were identified prospectively by clinical evaluation (BI, VK). All the patients with obliquely directed long axis of the disc, oblique direction of vessels and retinal pigment epithelial conus were included in the study. Best corrected visual acuity, slit-lamp examination, optic disc measurements, keratometry and refraction were recorded. Results: Twenty four patients (41 eyes) were recruited for the study. Eighteen (75%) patients had bilateral tilted optic discs. Eighteen patients (75%) were females and six (25%) were males. The mean age was 62 years(range 9 – 86 years). 76% of the patients were myopic and 24% hypermetropic. The mean spherical equivalent was –7.49 dioptres (SD 1.7D, range +6D to -17D). The mean corneal astigmatism was 1.09D (SD 0.9D, range 0.25D to 3.80D). The 6 patients who had unilateral, untilted discs were used as a control group to compare their mean corneal astigmatism (1.32 D) with the rest. Student "t" test was performed. ("p" = 0.49). Conclusions: In our study, tilted disc syndrome was found to be largely bilateral and more commonly seen in females. Myopia was the commonest refractive error associated with this clinical condition. However, 24% of patients in this series were hypermetropic. No correlation between the tilting of the optic disc and significant corneal astigmatism was noted as previously reported.

Developing Students’ Mathematical Thinking and Algorithmic Culture in IT Classes

Report published in the Proceedings of the National Conference on "Education in the Information Society", Plovdiv, May, 2012

Identification, distribution, and probability of infection in sympatric gastropods by digenean parasites at Pa-hay-okee, Everglades National Park using molecules and morphology

In this study, I determined the identity, taxonomic placement, and distribution of digenetic trematodes parasitizing the snails Pomacea paludosa and Planorbella duryi at Pa-hay-okee, Everglades National Park. I also characterized temporal and geographic variation in the probability of parasite infection for these snails based on two years of sampling. Although studies indicate that digenean parasites may have important effects both on individual species and the structure of communities, there have been no studies of digenean parasitism on snails within the Everglades ecosystem. For example, the endangered Everglade Snail Kite, a specialist that feeds almost exclusively on Pomacea paludosa, and is known to be a definitive host of digenean parasites, may suffer direct and indirect effects from consumption of parasitized apple snails. Therefore, information on the diversity and abundance of parasites harbored in snail populations in the Everglades should be of considerable interest for management and conservation of wildlife. Juvenile digeneans (cercariae) representing 20 species were isolated from these two snails, representing a quadrupling of the number of species known. Species were characterized based on morphological, morphometric, and sequence data (18S rDNA, COI, and ITS). Species richness of shed cercariae from P. duryi was greater than P. paludosa, with 13 and 7 species respectively. These species represented 14 families. P. paludosa and P. duryi had no digenean species in common. Probability of digenean infection was higher for P. duryi than P. paludosa and adults showed a greater risk of infection than juveniles for both of these snails. Planorbella duryi showed variation in probability of infection between sampling sites and hydrological seasons. The number of unique combinations of multi-species infections was greatest among P. duryi individuals, while the overall percentage of multi-species infections was greatest in P. paludosa. Analyses of six frequently-observed multiple infections from P. duryi suggest the presence of negative interactions, positive interactions, and neutral associations between larval digeneans. These results should contribute to an understanding of the factors controlling the abundance and distribution of key species in the Everglades ecosystem and may in particular help in the management and recovery planning for the Everglade Snail Kite.

A preliminary analysis of the correlation of food-web characteristics with hydrology and nutrient gradients in the southern Everglades

We estimated trophic position and carbon source for three consumers (Florida gar, Lepisosteus platyrhincus; eastern mosquitofish, Gambusia holbrooki; and riverine grass shrimp, Palaemonetes paludosus) from 20 sites representing gradients of productivity and hydrological disturbance in the southern Florida Everglades, U.S.A. We characterized gross primary productivity at each site using light/dark bottle incubation and stem density of emergent vascular plants. We also documented nutrient availability as total phosphorus (TP) in floc and periphyton, and the density of small fishes. Hydrological disturbance was characterized as the time since a site was last dried and the average number of days per year the sites were inundated for the previous 10 years. Food-web attributes were estimated in both the wet and dry seasons by analysis of δ15N (trophic position) and δ13C (food-web carbon source) from 702 samples of aquatic consumers. An index of carbon source was derived from a two-member mixing model with Seminole ramshorn snails (Planorbella duryi) as a basal grazing consumer and scuds (amphipods Hyallela azteca) as a basal detritivore. Snails yielded carbon isotopic values similar to green algae and diatoms, while carbon values of scuds were similar to bulk periphyton and floc; carbon isotopic values of cyanobacteria were enriched in C13compared to all consumers examined. A carbon source similar to scuds dominated at all but one study site, and though the relative contribution of scud-like and snail-like carbon sources was variable, there was no evidence that these contributions were a function of abiotic factors or season. Gar consistently displayed the highest estimated trophic position of the consumers studied, with mosquitofish feeding at a slightly lower level, and grass shrimp feeding at the lowest level. Trophic position was not correlated with any nutrient or productivity parameter, but did increase for grass shrimp and mosquitofish as the time following droughts increased. Trophic position of Florida gar was positively correlated with emergent plant stem density.

Designing for Dual Submission of ETDs

The main objective is to get participants thinking about how they can solve problems associated with a dual submission of ETDs. Many institutions choose to archive ETDs in their repositories, but also mandate, insist, or permit ETDs to be submitted to ProQuest via the UMI ETD Administrator. The Administrator offers a no-submission-fee route for ETD inclusion in ProQuest’s ubiquitous subscription databases. At FIU, after deciding on a mandatory ETD Policy in July 2011, we considered moving from a payment/snail mail submission to altogether scrapping submission to ProQuest; however, our librarians made a case for keeping at least an option for ProQuest submission. After consideration of all the options, implementing the UMI ETD Administrator seemed the most logical because it relieves payment, paperwork, and snail mail. Unfortunately, the UMI ETD Administrator creates as many problems as it solves e.g., the dual submission. According to the Berkman Center’s Good Practices for University Open-Access Policies, the university should offer to make additional deposits outside of the institutional repository. Thus, we sought to find a way for the students to only submit once to our DigitalCommons Institutional Repository. By June 2012, we manually triaged our first batch of ETDs from our DigitalCommons to the UMI ETD Administrator; however, since that first batch we have identified problems with metadata submission, entering student information, and the ETD Administrator default setup. For instance, with our second batch, we eliminated discrepancies with the department field; in our third batch, we eliminated concerns with FERPA and submitting student information; in our fourth batch, we look to cut down the time of each manual submission. Attendees, with institutions considering the ETD Administrator, should expect to anticipate and solve several issues associated with implementing the system in conjunction with an institutional repository. Attendees, who work with both the ETD Administrator and an Institutional Repository, should expect to gain new ideas for eliminating a dual submission for students, a quicker publication turn around, and/or decreased workflow time.

A Suite of Prey Traits Determine Predator and Nutrient Enrichment Effects in a Tri-Trophic Food Chain

Predation, predation risk, and resource quality affect suites of prey traits that collectively impact individual fitness, population dynamics, and community structure. However, studies of multi-trophic level effects generally focus on a single prey trait, failing to capture trade-offs among suites of covarying traits that govern population responses and emergent community patterns. We used structural equation models (SEM) to summarize the non-lethal and lethal effects of crayfish, Procambarus fallax, and phosphorus (P) addition, which affected prey food quality (periphyton), on the interactive effects of behavioral, morphological, developmental, and reproductive traits of snails, Planorbella duryi. Univariate and multivariate analyses suggested trade-offs between production (growth, reproduction) and defense (foraging behavior, shell shape) traits of snails in response to non-lethal crayfish and P addition, but few lethal effects. SEM revealed that non-lethal crayfish effects indirectly limited per capita offspring standing stock by increasing refuge use, slowing individual growth, and inducing snails to produce thicker, compressed shells. The negative effects of non-lethal crayfish on snails were strongest with P addition; snails increased allocation to shell defense rather than growth or reproduction. However, compared to ambient conditions, P addition with non-lethal crayfish still yielded greater per capita offspring standing stock by speeding individual snail growth enabling them to produce more offspring that also grew faster. Increased refuge use in response to non-lethal crayfish led to a non-lethal trophic cascade that altered the spatial distribution of periphyton. Independent of crayfish effects, snails stimulated periphyton growth through nutrient regeneration. These findings illustrate the importance of studying suites of traits that reveal costs associated with inducing different traits and how expressing those traits impacts population and community level processes.

Data compilation on the biological response to ocean acidification: environmental and experimental context of data sets and related literature

The exponential growth of studies on the biological response to ocean acidification over the last few decades has generated a large amount of data. To facilitate data comparison, a data compilation hosted at the data publisher PANGAEA was initiated in 2008 and is updated on a regular basis (doi:10.1594/PANGAEA.149999). By January 2015, a total of 581 data sets (over 4 000 000 data points) from 539 papers had been archived. Here we present the developments of this data compilation five years since its first description by Nisumaa et al. (2010). Most of study sites from which data archived are still in the Northern Hemisphere and the number of archived data from studies from the Southern Hemisphere and polar oceans are still relatively low. Data from 60 studies that investigated the response of a mix of organisms or natural communities were all added after 2010, indicating a welcomed shift from the study of individual organisms to communities and ecosystems. The initial imbalance of considerably more data archived on calcification and primary production than on other processes has improved. There is also a clear tendency towards more data archived from multifactorial studies after 2010. For easier and more effective access to ocean acidification data, the ocean acidification community is strongly encouraged to contribute to the data archiving effort, and help develop standard vocabularies describing the variables and define best practices for archiving ocean acidification data.

Steroid Androgen Exposure during Development Has No Effect on Reproductive Physiology of Biomphalaria glabrata

Funding: The research presented in this manuscript was wholly funded by National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), https://www.nc3rs.org.uk/. ‘The Snail Assay as an Alternative to the Rodent Hershberger Assay for Detecting Androgens and Anti-androgens’ funding reference: G0900802/1 to SJ, EJR, CSJ, and LRN. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Bird predation experiments in tropical agroforestry landscapes of the Napu Valley in Central Sulawesi, Indonesia

We performed bird predation experiments (dummy experiments), using artificial prey and bird community data to investigate the importance of predator diversity vs. predator identity in cacao agroforestry landscapes. All sample sites were situated at the northern tip of Napu Valley in Central Sulawesi, Indonesia. After an initial mapping of the study area, we selected 15 smallholder cacao plantations as sites for our exclosure experiments in March 2010. For our predation experiment, we selected 10 (out of 15) study sites and 5 cacao trees per site for the application of artificial prey for birds (dummy caterpillars made of plasticine). Our study trees (numbered from 1 to 5 per site) were randomly chosen and we kept spacing of at least two unmanipulated cacao trees between two study trees to avoid clumped distribution. To quantify both daytime/diurnal predation and night-time/nocturnal predation (e.g. birds vs. bats), we applied 7 caterpillar dummies on all study trees and controlled them for predation marks in the early morning (05:00-06:00 am), in the evening (17:00-18:00 pm) and in the early morning on the next day (completing one survey round). In total, we performed four survey rounds per study site (in June and July 2011). The caterpillar dummies were always applied in the same order and on three different parts of each cacao study tree: One 'control dummy' (located on first branching of the cacao tree); 3 'branch dummies' (located on one main branch coming from first branching; 20-25 cm between single dummies) and 3 'leaf dummies' (3 medium aged cacao trees adjacent to main branch were selected and single dummies placed in the center of each cacao leaf). The different positions were chosen to control for different foraging modes of predators (e.g. branch gleaners versus leaf gleaners). During day- and nighttime surveys, we controlled if the dummy caterpillars were still present in their original position, if they were absent and could not be relocated on the ground or if they were fallen to the ground, but could still be recorded. Eaten dummies were counted as 1 mark usually, except for those dummies, where two or more different kind of arthropods had eaten parts of the dummy (2 marks or more). Other predation marks were added to this number. For each dummy, we counted the total number of different predation marks. We focused on predation marks that could be identified with certainty (based on preliminary observations and/or literature): marks of birds, rodents and snails. Finally, we analysed the relationship of bird predation marks and bird community parameters (abundance vs. diversity), as well as effects of local and landscape management on the avian predation success.

Exploring molecular variation in Schistosoma japonicum in China

Schistosomiasis is a neglected tropical disease that affects more than 200 million people worldwide. The main disease-causing agents, Schistosoma japonicum, S. mansoni and S. haematobium, are blood flukes that have complex life cycles involving a snail intermediate host. In Asia, S. japonicum causes hepatointestinal disease (schistosomiasis japonica) and is challenging to control due to a broad distribution of its snail hosts and range of animal reservoir hosts. In China, extensive efforts have been underway to control this parasite, but genetic variability in S. japonicum populations could represent an obstacle to eliminating schistosomiasis japonica. Although a draft genome sequence is available for S. japonicum, there has been no previous study of molecular variation in this parasite on a genome-wide scale. In this study, we conducted the first deep genomic exploration of seven S. japonicum populations from mainland China, constructed phylogenies using mitochondrial and nuclear genomic data sets, and established considerable variation between some of the populations in genes inferred to be linked to key cellular processes and/or pathogen-host interactions. Based on the findings from this study, we propose that verifying intraspecific conservation in vaccine or drug target candidates is an important first step toward developing effective vaccines and chemotherapies against schistosomiasis.

Advances in the Diagnosis of Human Schistosomiasis

Schistosomiasis is a major neglected tropical disease that afflicts more than 240 million people, including many children and young adults, in the tropics and subtropics. The disease is characterized by chronic infections with significant residual morbidity and is of considerable public health importance, with substantial socioeconomic impacts on impoverished communities. Morbidity reduction and eventual elimination through integrated intervention measures are the focuses of current schistosomiasis control programs. Precise diagnosis of schistosome infections, in both mammalian and snail intermediate hosts, will play a pivotal role in achieving these goals. Nevertheless, despite extensive efforts over several decades, the search for sensitive and specific diagnostics for schistosomiasis is ongoing. Here we review the area, paying attention to earlier approaches but emphasizing recent developments in the search for new diagnostics for schistosomiasis with practical applications in the research laboratory, the clinic, and the field. Careful and rigorous validation of these assays and their cost-effectiveness will be needed, however, prior to their adoption in support of policy decisions for national public health programs aimed at the control and elimination of schistosomiasis.

Gelsolin-mediated activation of PI3K/Akt pathway is crucial for hepatocyte growth factor-induced cell scattering in gastric carcinoma

In gastric cancer (GC), the main subtypes (diffuse and intestinal types) differ in pathological characteristics, with diffuse GC exhibiting early disseminative and invasive behaviour. A distinctive feature of diffuse GC is loss of intercellular adhesion. Although widely attributed to mutations in the CDH1 gene encoding E-cadherin, a significant percentage of diffuse GC do not harbor CDH1 mutations. We found that the expression of the actin-modulating cytoskeletal protein, gelsolin, is significantly higher in diffuse-type compared to intestinal-type GCs, using immunohistochemical and microarray analysis. Furthermore, in GCs with wild-type CDH1, gelsolin expression correlated inversely with CDH1 gene expression. Downregulating gelsolin using siRNA in GC cells enhanced intercellular adhesion and E-cadherin expression, and reduced invasive capacity. Interestingly, hepatocyte growth factor (HGF) induced increased gelsolin expression, and gelsolin was essential for HGF-medicated cell scattering and E-cadherin transcriptional repression through Snail, Twist and Zeb2. The HGF-dependent effect on E-cadherin was found to be mediated by interactions between gelsolin and PI3K-Akt signaling. This study reveals for the first time a function of gelsolin in the HGF/cMet oncogenic pathway, which leads to E-cadherin repression and cell scattering in gastric cancer. Our study highlights gelsolin as an important pro-disseminative factor contributing to the aggressive phenotype of diffuse GC.