Relative expression of genes of terpene metabolism in different tissues of Artemisia annua L

Background  

Recently, Artemisia annua L. (annual or sweet wormwood) has received increasing attention due to the fact that the plant produces the sesquiterpenoid endoperoxide artemisinin, which today is widely used for treatment of malaria. The plant produces relatively small amounts of artemisinin and a worldwide shortage of the drug has led to intense research in order to increase the yield of artemisinin. In order to improve our understanding of terpene metabolism in the plant and to evaluate the competition for precursors, which may influence the yield of artemisinin, we have used qPCR to estimate the expression of 14 genes of terpene metabolism in different tissues.     

Linking past cultural developments to palaeoenvironmental changes in Estonia

Connections between environmental and cultural changes are analysed in Estonia during the past c. 4,500 years. Records of cereal-type pollen as (agri)cultural indices are compared with high-resolution palaeohydrological and annual mean temperature reconstructions from a selection of Estonian bogs and lakes (and Lake Igelsjön in Sweden). A broad-scale comparison shows increases in the percentage of cereal-type pollen during a decreasing trend in annual mean temperatures over the past c. 4,300 years, suggesting a certain independence of agrarian activities from environmental conditions at the regional level. The first cereal-type pollen in the region is found from a period with a warm and dry climate. A slow increase in pollen of cultivated land is seen around the beginning of the late Bronze Age, a slight increase at the end of the Roman Iron Age and a significant increase at the beginning of the Middle Ages. In a few cases increases in agricultural pollen percentages occur in the periods of warming. Stagnation and regression occurs in the periods of cooling, but regression at individual sites may also be related to warmer climate episodes. The cooling at c. 400–300 cal b.p., during the ‘Little Ice Age’ coincides with declines in cereal-type and herb pollen curves. These may not, however, be directly related to the climate change, because they coincide with war activities in the region.     

New evidence of possible crop introduction to north-eastern Europe during the Stone Age

Long term (from the Mesolithic to the Bronze Age) habitation of the Akali settlement on a clearly defined bog-island in East Estonia is used as an example of transitional development from a prosperous foragers’ habitation centre to a hinterland of established farming cultures, taking place through availability, substitution and consolidation phases of crop farming in the boreal forest zone. The pre-Neolithic finds of Triticum and Cannabis t. pollen at c. 5600 b.c. are interpreted as possible indications of the acquaintance of foragers with farming products, through contacts with central European agrarian tribes during the availability phase. The substitution phase is marked by more or less scattered pollen finds of various cereals and hemp and, at Akali, is connected with Neolithic period 4900–1800 b.c. An increasing importance of crop farming in the economy is characteristic of the consolidation phase, but because natural conditions are unfavourable for arable land-use, a regression of human presence is recorded during the second part of the Neolithic. The settlement was abandoned during the Bronze Age at the time when crop farming become the basis of the economy in Estonia. The re-colonisation of the area, traced to ca. a.d. 1200, took place for political reasons rather than through increasing suitability of the landscape.Editorial responsibility: Felix Bittmann     

Unexpectedly diverse forest dung beetle communities in degraded rain forest landscapes in Madagascar

Tropical forests, which harbor high levels of biodiversity, are being lost at an alarming speed. Madagascar, a biodiversity hotspot, has lost more than half of its original forest cover. Most of the remaining forests are small fragments of primary and secondary forest with differing degrees of human impact. These forests, as well as coffee and fruit plantations, may be important in supporting the forest-dependent biodiversity in Madagascar but this has been little studied. In Madagascar, dung beetles, which offer important ecosystem services, are largely restricted to forests. We examined the ability of fragmented and degraded forests to support dung beetle diversity, compared to the large areas of primary forest in eastern Madagascar. We found a general trend of a reduction of species with a loss of forest connectivity. In contrast, a higher level of forest disturbance was associated with higher species diversity. In several sites of low-quality forest as many or more species were found as in less disturbed and primary forests. The average size of dung beetles was smaller in the lower quality localities than in the primary forests. These findings suggest that many forest dung beetles in Madagascar are better adapted to forest disturbance than earlier expected, although they require some level of connectivity to surrounding forest.     

Seabird Guano Fertilizes Baltic Sea Littoral Food Webs

Nutrient enrichment in coastal marine systems can have profound impacts on trophic networks. In the Baltic Sea, the population of Great Cormorant (Phalacrocorax carbo sinensis) has increased nearly exponentially since the mid-1990s, and colonies of these seabirds can be important sources of nitrogen enrichment for nearby benthic communities due to guano runoff. In this study we used stable isotope analyses and diet mixing models to determine the extent of nitrogen enrichment from cormorant colonies, as well as to examine any possible changes in herbivore diet preferences due to enrichment. We found significantly higher levels of δ¹⁵N in samples from colony islands than control islands for producers (the dominant macroalga Fucus vesiculosus, filamentous algae, and periphyton) and herbivores, as well as a positive correlation between enrichment and nest density in colony sites. We also found that enrichment increased over the breeding season of the cormorants, with higher enrichment in late summer than early summer. While the amount of total nitrogen did not differ between colony and control sites, the amount of guano-based nitrogen in algae was >50% in most sites, indicating high nitrogen enrichment from colonies. Herbivores (the isopod Idotea balthica and the gastropod Theodoxus fluviatilis) preferred feeding upon the dominant macroalga Fucus vesiculosus rather than on filamentous algae or periphyton in both control and colony, and there was a significant increase in periphyton consumption near colony sites. Overall, guano from cormorant colonies seems to have effects on both producers and herbivores, as well as the potential to modify algae-herbivore interactions.     

Mitochondrial function in Antarctic nototheniids with ND6 translocation

Fish of the suborder Notothenioidei have successfully radiated into the Southern Ocean and today comprise the dominant fish sub-order in Antarctic waters in terms of biomass and species abundance. During evolution in the cold and stable Antarctic climate, the Antarctic lineage of notothenioids developed several unique physiological adaptations, which make them extremely vulnerable to the rapid warming of Antarctic waters currently observed. Only recently, a further phenomenon exclusive to notothenioid fish was reported: the translocation of the mitochondrial gene encoding the NADH Dehydrogenase subunit 6 (ND6), an indispensable part of complex I in the mitochondrial electron transport system.This study investigated the potential physiological consequences of ND6 translocation for the function and thermal sensitivity of the electron transport system in isolated liver mitochondria of the two nototheniid species Notothenia coriiceps and Notothenia rossii, with special attention to the contributions of complex I (NADH DH) and complex II (Succinate DH) to oxidative phosphorylation. Furthermore, enzymatic activities of NADH:Cytochrome c Oxidoreductase and Cytochrome C Oxidase were measured in membrane-enriched tissue extracts.During acute thermal challenge (0-15°C), capacities of mitochondrial respiration and enzymatic function in the liver could only be increased until 9°C. Mitochondrial complex I (NADH Dehydrogenase) was fully functional but displayed a higher thermal sensitivity than the other complexes of the electron transport system, which may specifically result from its unique amino acid composition, revealing a lower degree of stability in notothenioids in general. We interpret the translocation of ND6 as functionally neutral but the change in amino acid sequence as adaptive and supportive of cold stenothermy in Antarctic nototheniids. From these findings, an enhanced sensitivity to ocean warming can be deduced for Antarctic notothenioid fish.     

Stereoselective oxidation of regioisomeric octadecenoic acids by fatty acid dioxygenases

Seven Z-octadecenoic acids having the double bond located in positions 6Z to 13Z were photooxidized. The resulting hydroperoxy-E-octadecenoic acids [HpOME(E)] were resolved by chiral phase-HPLC-MS, and the absolute configurations of the enantiomers were determined by gas chromatographic analysis of diastereoisomeric derivatives. The MS/MS/MS spectra showed characteristic fragments, which were influenced by the distance between the hydroperoxide and carboxyl groups. These fatty acids were then investigated as substrates of cyclooxygenase-1 (COX-1), manganese lipoxygenase (MnLOX), and the (8R)-dioxygenase (8R-DOX) activities of two linoleate diol synthases (LDS) and 10R-DOX. COX-1 and MnLOX abstracted hydrogen at C-11 of (12Z)-18:1 and C-12 of (13Z)-18:1. (11Z)-18:1 was subject to hydrogen abstraction at C-10 by MnLOX and at both allylic positions by COX-1. Both allylic hydrogens of (8Z)-18:1 were also abstracted by 8R-DOX activities of LDS and 10R-DOX, but only the allylic hydrogens close to the carboxyl groups of (11Z)-18:1 and (12Z)-18:1. 8R-DOX also oxidized monoenoic C(14)-C(20) fatty acids with double bonds at the (9Z) position, suggesting that the length of the omega end has little influence on positioning for oxygenation. We conclude that COX-1 and MnLOX can readily abstract allylic hydrogens of octadecenoic fatty acids from C-10 to C-12 and 8R-DOX from C-7 and C-12.     

The Global Burden of Childhood Coeliac Disease: A Neglected Component of Diarrhoeal Mortality?

Objectives

Coeliac disease has emerged as an increasingly recognised public health problem over the last half-century, and is now coming to be seen as a global phenomenon, despite a profound lack of globally representative epidemiological data. Since children with coeliac disease commonly present with chronic diarrhoea and malnutrition, diagnosis is often overlooked, particularly in poorer settings where children often fail to thrive and water-borne infectious diarrhoeas are common. This is the first attempt to make global estimates of the burden of coeliac disease in childhood.

Methods

We built a relatively crude model of childhood coeliac disease, incorporating estimates of population prevalence, probability of non-diagnosis, and likelihood of mortality among the undiagnosed across all countries from 1970 to 2010, based around the few available data. All our assumptions are stated in the paper and the model is available as a supplementary file.

Findings

Our model suggests that in 2010 there were around 2.2 million children under 5 years of age living with coeliac disease. Among these children there could be 42,000 deaths related to coeliac disease annually. In 2008, deaths related to coeliac disease probably accounted for approximately 4% of all childhood diarrhoeal mortality.

Conclusions

Although coeliac disease may only account for a small proportion of diarrhoeal mortality, these deaths are not preventable by applying normal diarrhoea treatment guidelines, which may even involve gluten-based food supplements. As other causes of diarrhoeal mortality decline, coeliac disease will become a proportionately increasing problem unless consideration is given to trying gluten-free diets for children with chronic diarrhoea and malnutrition.     

Patterns of <Emphasis Type="Italic">Bythotrephes longimanus</Emphasis> distribution relative to native macroinvertebrates and zooplankton prey

As exotic species are introduced and spread across a heterogeneous landscape, the abundance and richness of potential competitor and prey species they encounter will vary. Little is known about the interactions between Bythotrephes longimanus and native predatory macroinvertebrates (e.g., Mysis, Chaoborus), which potentially limit the establishment and spread of the invader. An 80-lake survey was conducted in the summer of 2007 to obtain macroinvertebrate abundances across invaded and non-invaded lakes. A subset (15) of these lakes was surveyed more intensively to obtain stratified daytime and night-time distributions of the organisms. Overall co-occurrence of Bythotrephes with native macroinvertebrate predators was widespread across lakes indicating that the presence of native macroinvertebrates alone is unlikely to limit the establishment of Bythotrephes. However, we did find an effect of native macroinvertebrate predators on the vertical distribution of Bythotrephes: as native macroinvertebrate abundances increased, the relative abundance of Bythotrephes in the epilimnion increased. Furthermore, the relative abundance of some zooplankton prey (e.g., Daphnia) was lower in the epilimnion when Bythotrephes abundance was high. Although we cannot rule out consumptive effects, some evidence suggests an avoidance behavioural response in the prey. While the underlying mechanisms of these distributional shifts remain unclear, our results suggest that interactions between Bythotrephes, native macroinvertebrates and zooplankton prey are complex, highlighting the need to further examine these interactions.