Hypermethylation in the ZBTB20 gene is associated with major depressive disorder

Background

Although genetic variation is believed to contribute to an individual’s susceptibility to major depressive disorder, genome-wide association studies have not yet identified associations that could explain the full etiology of the disease. Epigenetics is increasingly believed to play a major role in the development of common clinical phenotypes, including major depressive disorder.

Results

Genome-wide MeDIP-Sequencing was carried out on a total of 50 monozygotic twin pairs from the UK and Australia that are discordant for depression. We show that major depressive disorder is associated with significant hypermethylation within the coding region of ZBTB20, and is replicated in an independent cohort of 356 unrelated case-control individuals. The twins with major depressive disorder also show increased global variation in methylation in comparison with their unaffected co-twins. ZBTB20 plays an essential role in the specification of the Cornu Ammonis-1 field identity in the developing hippocampus, a region previously implicated in the development of major depressive disorder.

Conclusions

Our results suggest that aberrant methylation profiles affecting the hippocampus are associated with major depressive disorder and show the potential of the epigenetic twin model in neuro-psychiatric disease.     

Use of Meta-Analysis to Assess the Effect of Conventional Water Treatment Methods on the Prevalence of Cryptosporidium Spp. in Drinking Water

Meta-analysis is defined as the statistical analysis of a collection of analytic results for the purpose of integrating the findings. However, its use in environmental and agricultural health protection has been minor in research to date. Few meta-analysis studies have been applied to assess factors relating to Cryptosporidium but none have examined the effect of conventional water treatment on oocyst prevalence. The objective of this study was to synthesize past scientific research and analyze the effects of conventional water treatment methods on the prevalence of Cryptosporidium in drinking water using a traditional parametric approach of meta-analysis. Twenty-three different published studies featuring 27 separate water treatment surveys were identified for inclusion in the meta-analysis. The meta-analysis indicated that general conventional water treatment methods reduced Cryptosporidium occurrence in drinking water by an average factor of ～11.82 (95% CI = 2.7–52.5). Results highlight the resistance of the pathogen to such treatment methods and emphasize the parasites standing as a waterborne pathogen of primary concern given the possibility of viable oocyst occurrence in water, post treatment. Consequently, findings accentuate the need for new approaches to the control of Cryptosporidium aimed at integrated catchment management, source protection, and also including new treatment technologies. Until such approaches are actively adopted the potential risk posed to consumers by pathogens in potable water will remain active.     

Compensatory development in preimplantation mouse embryos derived from delayed mating.

Rodent embryos resulting from delayed mating grow relatively faster than those resulting from normal mating. To evaluate this phenomenon quantitatively, in the present study we compared the number of cells at the preimplantation stage of mouse embryos derived from normal mating and those derived from delayed mating (3 and 6 h after ovulation). The mean cell numbers (45.4 and 43.0 for delayed mating at 3 and 6 h postovulation, respectively) of embryos at 77 h postcoitus (hpc) in the delayed mating groups were greater than that (38.4) of the normal mating group. Further, when the mean cell numbers (38.8 and 38.5) in the delayed mating groups were counted at 74 hpc, they were almost equal to that of the normal mating group at 77 hpc. The study demonstrated that preimplantation mouse embryos derived from delayed mating progress more rapidly than their normally mated counterparts. However, a 3-h advance in development seems to be the limit of this increased rate of growth, even when the time interval from ovulation to mating is longer than 3 h. The mechanism(s) of this interesting compensatory phenomenon should be investigated.     

Microbial Exposure Assessment of Waterborne Pathogens

The large number of waterborne illnesses in Ireland and worldwide has highlighted the need to enhance strategies that minimize human exposure to pathogens in drinking water supplies. Waterborne pathogens of public concern together with relevant national and international legislation are reviewed in this study. Cryptosporidium species and pathogenic Escherichia coli are among pathogens of primary concern. The organisms originate from the gastrointestinal tract of animals and humans. They may be associated with persistent contamination of water sources, survive for long periods in the environment, and, in particular in the case of Cryptosporidium species, may survive in chlorinated water supplies. Prevention of waterborne infection should emphasize source protection in addition to water treatment. Risk assessment models can play an important role in protecting natural water systems from contamination with these pathogens. Qualitative approaches can provide an effective means of assessing risks with minimum resources and limited data; however, they lack the precision and predictive ability of fully quantitative approaches. Thirteen quantitative simulation models that could potentially be used for modeling bacterial pollutants in agricultural watersheds have been assessed in this study. No one model suits all modeling criteria. Pathogen predictions have proved variable and no model was capable of accounting for all geological and hydrological factors in addition to modeling the physical transport of bacteria in surface runoff. This assessment summarizes commonly used models and their capacity to model water pollution while also providing a good reference point for the microbial risk assessment of waterborne pathogens.     

Human Risks from the Combustion of SRM-Derived Tallow in Ireland

The identification of meat and bone meal (MBM) as a significant factor in the spread of bovine spongiform encephalopathy (BSE) has resulted in the introduction of restrictions on the use and movement of MBM and tallow. This has led to a requirement for alternative uses for these products. This paper reports on a risk assessment performed on the use of tallow as a fuel oil extender in diesel engines. With up to 4000 tonnes of tallow being produced each year in Ireland, combustion with energy recovery represents a viable, cost-efficient utilization route. A stochastic (Latin Hypercube sampling) simulation model was developed to assess the infectiv-ity risk to humans associated with potential airborne exposure to the combustion products when using tallow as a combustion fuel in diesel engines. The model simulates the potential infectivity pathways that tallow follows, including its production from animals with potentially subclinical BSE and processing the tallow with segregation and heat treatments. The model uses probability distributions for the most important input parameters. The assessment takes into account a number of epidemiological parameters that include tissue infectivity, species barrier, disease incidence, and heat inactivation. Two scenarios, reflecting the infectivity risk in different animal tissues defined by the European Commissions Scientific Steering Committee (SSC), were performed. It is seen from the model results that the risk of a human contracting variant Creutzfeldt-Jakob Disease (vCJD) from potential airborne exposure to BSE, resulting from the combustion of tallow, is extremely small even when model uncertainty is taken into account (mean individual risk values ranging from 10^-11.43 to 10^-7.23 per year/person). The risks are a number of orders of magnitude less than the sporadic annual incidence level of Creutzfeldt-Jakob Disease 9CJD) in Europe (approximately 10^-6)