Escalating Worldwide use of Urea – A Global Change Contributing to Coastal Eutrophication

While the global increase in the use of nitrogen-based fertilizers has been well recognized, another change in fertilizer usage has simultaneously occurred: a shift toward urea-based products. Worldwide use of urea has increased more than 100-fold in the past 4 decades and now constitutes >50% of global nitrogenous fertilizer usage. Global urea usage extends beyond agricultural applications; urea is also used extensively in animal feeds and in manufacturing processes. This change has occurred to satisfy the world’s need for food and more efficient agriculture. Long thought to be retained in soils, new data are suggestive of significant overland transport of urea to sensitive coastal waters. Urea concentrations in coastal and estuarine waters can be substantially elevated and can represent a large fraction of the total dissolved organic nitrogen pool. Urea is used as a nitrogen substrate by many coastal phytoplankton and is increasingly found to be important in the nitrogenous nutrition of some harmful algal bloom (HAB) species. The global increase from 1970 to 2000 in documented incidences of paralytic shellfish poisoning, caused by several HAB species, is similar to the global increase in urea use over the same 3 decades. The trend toward global urea use is expected to continue, with the potential for increasing pollution of sensitive coastal waters around the world.     

Climate Change and Spatiotemporal Distributions of Vector-Borne Diseases in Nepal – A Systematic Synthesis of Literature

Background

Despite its largely mountainous terrain for which this Himalayan country is a popular tourist destination, Nepal is now endemic for five major vector-borne diseases (VBDs), namely malaria, lymphatic filariasis, Japanese encephalitis, visceral leishmaniasis and dengue fever. There is increasing evidence about the impacts of climate change on VBDs especially in tropical highlands and temperate regions. Our aim is to explore whether the observed spatiotemporal distributions of VBDs in Nepal can be related to climate change.

Methodology

A systematic literature search was performed and summarized information on climate change and the spatiotemporal distribution of VBDs in Nepal from the published literature until December2014 following providing items for systematic review and meta-analysis (PRISMA) guidelines.

Principal Findings

We found 12 studies that analysed the trend of climatic data and are relevant for the study of VBDs, 38 studies that dealt with the spatial and temporal distribution of disease vectors and disease transmission. Among 38 studies, only eight studies assessed the association of VBDs with climatic variables. Our review highlights a pronounced warming in the mountains and an expansion of autochthonous cases of VBDs to non-endemic areas including mountain regions (i.e., at least 2,000 m above sea level). Furthermore, significant relationships between climatic variables and VBDs and their vectors are found in short-term studies.

Conclusion

Taking into account the weak health care systems and difficult geographic terrain of Nepal, increasing trade and movements of people, a lack of vector control interventions, observed relationships between climatic variables and VBDs and their vectors and the establishment of relevant disease vectors already at least 2,000 m above sea level, we conclude that climate change can intensify the risk of VBD epidemics in the mountain regions of Nepal if other non-climatic drivers of VBDs remain constant.     

Editor-in-Chief's Note

ＦｏｒｔｈｅｆｉｆｔｉｅｔｈａｎｎｉｖｅｒｓａｒｙｏｆｐｕｂｌｉｃａｔｉｏｎｏｆＡｃｔａＢｏｔａｎｉｃａＳｉｎｉｃａ，ｔｈｅｅｄｉｔｏｒｉａｌｄｅ ｐａｒｔｍｅｎｔ，ｈａｖｉｎｇｄｉｓｃｕｓｓｅｄｗｉｔｈｔｈｅｓｐｏｎｓｏｒｉｎｇｏｒｇａｎｉｚａｔｉｏｎｓ     

Coming to Terms with the Concept of Moving Species Threatened by Climate Change – A Systematic Review of the Terminology and Definitions

Intentional moving of species threatened by climate change is actively being discussed as a conservation approach. The debate, empirical studies, and policy development, however, are impeded by an inconsistent articulation of the idea. The discrepancy is demonstrated by the varying use of terms, such as assisted migration, assisted colonisation, or managed relocation, and their multiple definitions. Since this conservation approach is novel, and may for instance lead to legislative changes, it is important to aim for terminological consistency. The objective of this study is to analyse the suitability of terms and definitions used when discussing the moving of organisms as a response to climate change. An extensive literature search and review of the material (868 scientific publications) was conducted for finding hitherto used terms (N = 40) and definitions (N = 75), and these were analysed for their suitability. Based on the findings, it is argued that an appropriate term for a conservation approach relating to aiding the movement of organisms harmed by climate change is assisted migration defined as follows: Assisted migration means safeguarding biological diversity through the translocation of representatives of a species or population harmed by climate change to an area outside the indigenous range of that unit where it would be predicted to move as climate changes, were it not for anthropogenic dispersal barriers or lack of time. The differences between assisted migration and other conservation translocations are also discussed. A wide adoption of the clear and distinctive term and definition provided would allow more focused research on the topic and enable consistent implementation as practitioners could have the same understanding of the concept.     

Interaction of α-Chymotrypsin with Dimethyl Sulfoxide: A Change of Substrate Could “Change” the Interaction Mechanism

The kinetic behavior of -chymotrypsin was studied in water–DMSO mixtures at concentrations of the organic solvent that do not cause irreversible denaturation of the enzyme. Various substrates (N-substituted derivatives of L-tyrosine) were found to display substantially different kinetic patterns of interaction with -chymotrypsin, which can be described by totally different kinetic schemes. The differences were ascribed to competition between the N-acyl group of the substrate and the DMSO molecule at the S ₂ site of substrate binding to the active site of the enzyme.     

Changes in the Range of Some Common Rocky Shore Species in Britain – A Response to Climate Change?

Since the 1990s there has been a period of rapid climate warming in Europe. Long-term broad scale datasets coupled with time series at specific locations for rocky intertidal species dating back to the 1950s have been collected in Britain and Ireland. Resurveys of the original locations in 2001–2003 have been undertaken to identify changes in the biogeographical range and abundance of these species. The results show that some ‘southern’ species including Osilinus lineatus da Costa and Gibbula umbilicalis da Costa have undergone north and north-eastern range extensions. Populations have increased in abundance and adult size has decreased since the previous surveys were conducted. These changes have been synchronous throughout Britain, strongly suggesting that climate is responsible. The use of intertidal species as indicators of climate change is proposed.     

Here Today,Gone Tomorrow – Adaptation to Change in Memory-Guided Visual Search

Visual search for a target object can be facilitated by the repeated presentation of an invariant configuration of nontargets (‘contextual cueing’). Here, we tested adaptation of learned contextual associations after a sudden, but permanent, relocation of the target. After an initial learning phase targets were relocated within their invariant contexts and repeatedly presented at new locations, before they returned to the initial locations. Contextual cueing for relocated targets was neither observed after numerous presentations nor after insertion of an overnight break. Further experiments investigated whether learning of additional, previously unseen context-target configurations is comparable to adaptation of existing contextual associations to change. In contrast to the lack of adaptation to changed target locations, contextual cueing developed for additional invariant configurations under identical training conditions. Moreover, across all experiments, presenting relocated targets or additional contexts did not interfere with contextual cueing of initially learned invariant configurations. Overall, the adaptation of contextual memory to changed target locations was severely constrained and unsuccessful in comparison to learning of an additional set of contexts, which suggests that contextual cueing facilitates search for only one repeated target location.     

Biosynthesis of artemisinin – revisited

Artemisinin is a well-known antimalarial drug isolated from the Artemisia annua plant. The biosynthesis of this well-known molecule has been reinvestigated by using [1-¹³C]acetate, [2-¹³C]acetate, and [1,6-¹³C₂]glucose. The ¹³C peak enrichment in artemisinin was observed in six and nine carbon atoms from [1-¹³C]acetate and [2-¹³C]acetate, respectively. The ¹³C NMR spectra of ¹³C-enriched artemisinin suggested that the mevalonic acid (MVA) pathway is the predominant route to biosynthesis of this sesquiterpene. On the other hand, the peak enrichment of five carbons of ¹³C-artemisinin including carbon atoms originating from methyls of dimethylallyl group of geranyl pyrophosphate (GPP) and farnesyl pyrophosphate (FPP) was observed from [1,6-¹³C₂]glucose. This suggested that GPP which is supposed to be biosynthesized in plastids travels from plastids to cytosol through the plastidial wall and combines with isopentenyl pyrophosphate (IPP) to form the (E,E)-FPP which finally cyclizes and oxidizes to artemisinin. In this way the DXP pathway also contributes to the biosynthesis of this sesquiterpene.