University of East Anglia

About: University of East Anglia is a education organization based out in Norwich, Norfolk, United Kingdom. It is known for research contribution in the topics: Population & Climate change. The organization has 13250 authors who have published 37504 publications receiving 1669060 citations. The organization is also known as: UEA.

A 1,400-year tree-ring record of summer temperatures in Fennoscandia

Abstract: Tree-ring data have been used to reconstruct the mean summer (April-August) temperature of northern Fennoscandia for each year from AD 500 to the present. Summer temperatures have fluctuated markedly on annual, decadal and century timescales. There is little evidence for the existence of a Medieval Warm Epoch, and the Little Ice Age seems to be confined to the relatively short period between 1570 and 1650. This challenges the popular idea that these events were the major climate excursions of the first millennium, occurring synchronously throughout Europe in all seasons. An analysis of past warming trends suggests that any summer warming induced by greenhouse gases may not be detectable in this region until after 2030.

Rapid transcriptional plasticity of duplicated gene clusters enables a clonally reproducing aphid to colonise diverse plant species

Abstract: The prevailing paradigm of host-parasite evolution is that arms races lead to increasing specialisation via genetic adaptation. Insect herbivores are no exception and the majority have evolved to colonise a small number of closely related host species. Remarkably, the green peach aphid, Myzus persicae, colonises plant species across 40 families and single M. persicae clonal lineages can colonise distantly related plants. This remarkable ability makes M. persicae a highly destructive pest of many important crop species. To investigate the exceptional phenotypic plasticity of M. persicae, we sequenced the M. persicae genome and assessed how one clonal lineage responds to host plant species of different families. We show that genetically identical individuals are able to colonise distantly related host species through the differential regulation of genes belonging to aphid-expanded gene families. Multigene clusters collectively upregulate in single aphids within two days upon host switch. Furthermore, we demonstrate the functional significance of this rapid transcriptional change using RNA interference (RNAi)-mediated knock-down of genes belonging to the cathepsin B gene family. Knock-down of cathepsin B genes reduced aphid fitness, but only on the host that induced upregulation of these genes. Previous research has focused on the role of genetic adaptation of parasites to their hosts. Here we show that the generalist aphid pest M. persicae is able to colonise diverse host plant species in the absence of genetic specialisation. This is achieved through rapid transcriptional plasticity of genes that have duplicated during aphid evolution.

How Do Various Maize Crop Models Vary in Their Responses to Climate Change Factors

Abstract: Potential consequences of climate change on crop production can be studied using mechanistic crop simulation models. While a broad variety of maize simulation models exist, it is not known whether different models diverge on grain yield responses to changes in climatic factors, or whether they agree in their general trends related to phenology, growth, and yield. With the goal of analyzing the sensitivity of simulated yields to changes in temperature and atmospheric carbon dioxide concentrations [CO2], we present the largest maize crop model intercomparison to date, including 23 different models. These models were evaluated for four locations representing a wide range of maize production conditions in the world: Lusignan (France), Ames (USA), Rio Verde (Brazil) and Morogoro (Tanzania). While individual models differed considerably in absolute yield simulation at the four sites, an ensemble of a minimum number of models was able to simulate absolute yields accurately at the four sites even with low data for calibration, thus suggesting that using an ensemble of models has merit. Temperature increase had strong negative influence on modeled yield response of roughly -0.5 Mg ha(-1) per degrees C. Doubling [CO2] from 360 to 720 mu mol mol(-1) increased grain yield by 7.5% on average across models and the sites. That would therefore make temperature the main factor altering maize yields at the end of this century. Furthermore, there was a large uncertainty in the yield response to [CO2] among models. Model responses to temperature and [CO2] did not differ whether models were simulated with low calibration information or, simulated with high level of calibration information.

Bacterial respiration: a flexible process for a changing environment.

Abstract: The respiration of oxygen is fundamental to the life of higher animals and plants. The basic respiratory process in the mitochondria of these organisms involves the donation of electrons by low-redox-potential electron donors such as NADH. This is followed by electron transfer through a range of redox cofactors, bound to integral membrane or membrane-associated protein complexes. The process terminates in the reduction of the high-redox-potential electron acceptor, oxygen (Fig. 1). The free energy released during this electrontransfer process is used to drive the translocation of protons across the mitochondrial membrane to generate a trans-membrane proton electrochemical gradient or protonmotive force (∆p) that can drive the synthesis of ATP (Fig. 1). The respiratory flexibility of the mammalian mitochondrion is rather poor. There is some flexibility at the level of electron input (Fig. 1), but none at the level of electron output where cytochrome aa $ oxidase provides the only means of oxygen reduction. In the case of plant mitochondria, a slightly greater degree of respiratory flexibility is encountered with a number of alternative NADH dehydrogenases and two oxidases being apparent. This respiratory flexibility affords plant mitochondria with the capacity to contribute to processes other than the generation of ATP. For example, electron transfer from the alternative NADH dehydrogenase to the alternative oxidase is not coupled to the generation of ∆p and instead serves to release energy as heat, which can volatilize insect attractants to aid pollination. In the American skunk cabbage this same mechanism for heat production serves to permit growth at subzero temperatures (Nicholls & Ferguson, 1992). There is also some respiratory flexibility in the mitochondria of yeast, filamentous fungi and ancient protozoa, but it is amongst the Bacteria and Archaea that respiratory flexibility can be found at its most extreme. In these organisms, a diverse range of electron acceptors can be utilized including elemental sulphur and sulphur oxyanions (Hamilton, 1998), organic sulphoxides and sulphonates (Lie et al., 1999; McAlpine et al., 1998), nitrogen oxy-anions and nitrogen oxides (Berks et al., 1995), organic N-oxides (Czjzek et al., 1998), halogenated organics (Dolfing, 1990; Louie & Mohn, 1999; van de Pas et al., 1999), metalloid oxy-anions such as selenate and arsenate (Krafft & Macy, 1998; Macy et al., 1996, 1993; Schroder et al., 1997), transition metals such as Fe(III) and Mn(IV) (Lovley, 1991), and radionuclides such as U(VI) (Lovley & Phillips, 1992) and Tc(VII) (Lloyd et al., 1999). This respiratory diversity can be found amongst pyschrophiles, mesophiles and hyperthermophiles and contributes to the ability of prokaryotes to colonize many of Earth’s most hostile microoxic and anoxic environments.