Consideration of the bioavailability of metal/metalloid species in freshwaters: experiences regarding the implementation of biotic ligand model-based approaches in risk assessment frameworks

After the scientific development of Biotic Ligand Models (BLMs) in recent decades these models are now considered suitable for implementation in regulatory risk assessment of metals in freshwater bodies. The approach has been developed over several years and has been described in many peer-reviewed publications. The original complex BLMs have been applied in prospective risk assessment reports for metals and metal compounds and are also recommended as suitable concepts for the evaluation of monitoring data in the context of the European Water Framework Directive. Currently, several user-friendly BLM-based bioavailability software tools are available for assessing the aquatic toxicity of a limited number of metals (mainly copper, nickel, and zinc). These tools need only a basic set of water parameters as input (e.g., pH, hardness, dissolved organic matter and dissolved metal concentration). Such tools seem appropriate to foster the implementation in routine water quality assessments. This work aims to review the existing bioavailability-based regulatory approaches and the application of available BLM-based bioavailability tools for this purpose. Advantages and possible drawbacks of these tools (e.g., feasibility, boundaries of validity) are discussed, and recommendations for further implementation are given

Global occurrence, chemical properties, and ecological impacts of e-wastes (IUPAC technical report)

The waste stream of obsolete electronic equipment grows exponentially, creating a worldwide pollution and resource problem. Electrical and electronic waste (e-waste) comprises a heterogeneous mix of glass, plastics (including flame retardants and other additives), metals (including rare earth elements) and metalloids. The e-waste issue is complex and multi-faceted. In examining the different aspects of e-waste, informal recycling in developing countries has been identified as a primary concern due to widespread illegal shipments, weak environmental as well as health and safety regulations, lack of technology and inadequate waste treatment structure. For example, Nigeria, Ghana, India, Pakistan and China have all been identified as hotspots for the disposal of e-waste. This article presents a critical examination on the chemical nature of e-waste and the resulting environmental impacts on, for example, microbial biodiversity, flora and fauna in e-waste recycling sites around the world. It highlights the different types of risk assessment approaches required when evaluating the ecological impact of e-waste. Additionally, it presents examples of chemistry playing a role in potential solutions. The information presented here will be informative to relevant stakeholders to devise integrated management strategies to tackle this global environmental concern

ATP is required for the release of the anaphase-promoting complex/cyclosome from inhibition by the mitotic checkpoint

The mitotic (or spindle assembly) checkpoint system ensures accurate segregation of chromosomes by delaying anaphase until all chromosomes are correctly attached to the mitotic spindle. This system acts by inhibiting the activity of the anaphase-promoting complex/cyclosome (APC/C) ubiquitin ligase to target securin for degradation. APC/C is inhibited by a mitotic checkpoint complex (MCC) composed of BubR1, Bub3, Mad2, and Cdc20. The molecular mechanisms of the inactivation of the mitotic checkpoint, including the release of APC/C from inhibition, remain obscure. It has been reported that polyubiquitylation by the APC/C is required for the inactivation of the mitotic checkpoint [Reddy SK, Rape M, Margansky WA, Kirschner MW (2007) Nature, 446:921–924]. We confirmed the involvement of polyubiquitylation, but found that another process, which requires ATP cleavage at the β–γ position (as opposed to α–β bond scission involved in ubiquitylation), is essential for the release of APC/C from checkpoint inhibition. ATP (β–γ) cleavage is required both for the dissociation of MCC components from APC/C and for the disassembly of free MCC, whereas polyubiquitylation is involved only in the former process. We find that the requirement for ATP (β–γ) cleavage is not due to the involvement of the 26S proteasome and that the phenomena observed are not due to sustained activity of protein kinase Cdk1/cyclin B, caused by inhibition of the degradation of cyclin B. Thus, some other energy-consuming process is needed for the inactivation of the mitotic checkpoint

Comparison of Outcomes Parameters for Induction of Remission in New Onset Pediatric Crohn's Disease: Evaluation of the Porto IBD Group "Growth Relapse and Outcomes with Therapy" (GROWTH CD) Study.

BACKGROUND: Robust evaluation of induction therapies using both clinical and inflammatory outcomes in pediatric Crohn's disease (CD) are sparse. We attempted to evaluate clinical, inflammatory, and composite outcomes of induction of remission therapies (normal C reactive protein [CRP] remission) in a large pediatric prospective multicenter study. METHODS: Patients enrolled at diagnosis into the growth relapse and outcomes with therapy in Crohn's disease study were evaluated for disease activity, CRP, and fecal calprotectin at 8, 12 and 52 weeks after starting treatment. The primary endpoint was week-12 steroid-free remission defined by pediatric Crohn's disease activity index and CRP <0.5 mg/dL. The protocol required tapering off corticosteroids by week 11. RESULTS: We analyzed 222 patients (mean age, 12.9 +/- 3.2 yr) main evaluated treatment options included: 5-ASA (n = 29), exclusive enteral nutrition (n = 43), and corticosteroids (n = 114). Clinical remission at week 12 was achieved in 155 (73%) patients; both exclusive enteral nutrition and steroids were associated with normal CRP remission at week 12, although in a post hoc subgroup analysis exclusive enteral nutrition was superior in mild-to-moderate disease for this outcome. Among those in steroid-free remission in week 12, normal CRP predicted 1-year sustained remission (86% for normal CRP versus 61% for elevated CRP; P = 0.02). Baseline severity and early immunomodulation were similar in both groups. CONCLUSIONS: Normal CRP steroid-free remission at week 12 was impacted by type of induction therapy, but not by early immunomodulation. It was associated with more corticosteroids-free remission at week 52 and a trend for less relapses