bluuebunny/crossref_metadata_2025 huggingface dataset:
Deoxynivalenol and Nivalenol Accumulation in Wheat Infected with Fusarium graminearum During Grain Development
Authors: Yoshida Megumi , Nakajima Takashi
Published: July 2010

The manner in which deoxynivalenol (DON) and nivalenol (NIV) accumulation progresses in wheat grain infected with Fusarium graminearum and the influence of the time of infection on the accumulation of toxins were investigated. Four cultivars were tested in a greenhouse environment, where the plants were spray inoculated at three different stages with a mixture of DON and NIV chemotypes of F. graminearum. The results indicate that high levels of DON and NIV can be produced beyond 20 days after anthesis (DAA), even by early infection. The results of field experiments performed on seven cultivars, where inoculation was conducted using colonized maize kernel inoculum, were consistent with the greenhouse results. In addition, in the greenhouse experiments, late infection, at least as late as 20 DAA, caused grain contamination with these toxins even without clear disease symptoms on the spike. These results indicate the importance of the late stage in grain development in DON and NIV contamination, suggesting that control strategies that cover the late as well as the early stage of grain development should be established to effectively reduce the risk of these toxins' contaminating wheat.
Relationship Between Yearly Fluctuations in Fusarium Head Blight Intensity and Environmental Variables: A Window-Pane Analysis
Authors: Kriss A. B. , Paul P. A. , Madden L. V.
Published: July 2010

Window-pane methodology was used to determine the length and starting time of temporal windows where environmental variables were associated with annual fluctuations of Fusarium head blight (FHB) intensity in wheat. Initial analysis involved FHB intensity observations for Ohio (44 years), with additional analyses for Indiana (36 years), Kansas (28 years), and North Dakota (23 years). Selected window lengths of 10 to 280 days were evaluated, with starting times from approximate crop maturity back to the approximate time of planting. Associations were quantified with Spearman rank correlation coefficients. Significance for a given variable (for any window starting time in a collection of starting times) was declared using the Simes' multiplicity adjustment; at individual time windows, significant correlations were declared when the individual (unadjusted) P values were <0.005. In all states, moisture- or wetness-related variables (e.g., daily average relative humidity [RH] and total daily precipitation) were found to be positively correlated with FHB intensity for multiple window lengths and starting times; however, the highest correlations were primarily for shorter-length windows (especially 15 and 30 days) at similar starting times during the final 60 days of the growing season, particularly near the time of anthesis. This period encompasses spore production, dispersal, and fungal colonization of wheat spikes. There was no evidence of significant correlations between FHB and temperature-only variables for any time window; however, variables that combined aspects of moisture or wetness with temperature (e.g., duration of temperature between 15 and 30°C and RH ≥ 80%) were positively correlated with FHB intensity. Results confirm that the intensity of FHB in a region depends, at least in part, on environmental conditions during relatively short, critical time periods for epidemic development.
Numerical Studies of Biocontrol Efficacies of Foliar Plant Pathogens in Relation to the Characteristics of a Biocontrol Agent
Authors: Xu X.-M. , Salama N. , Jeffries P. , Jeger M. J.
Published: July 2010

A previously published generic mathematic model has been used in a numerical study to understand the dynamics of foliar pathogens in relation to mechanisms, and timing and coverage of biocontrol agent (BCA) applications. With the model parameter values used, it was demonstrated that a BCA possessing either competition or induced resistance as the main mechanism of biological control was more effective in reducing disease development than a BCA with either mycoparasitism or antibiosis as its mechanism. Application coverage, ranging from 50 to 90%, had little effect on biocontrol efficacy, particularly for a BCA with competition and induced resistance as the main mechanism of biocontrol. Conversely, delayed application of BCA had more profound effects on biocontrol efficacy for those with competition or induced resistance as their main mechanism than those with mycoparasitism and antibiosis. Biocontrol efficacy was greatest for a single BCA combining competition with mycoparasitism or antibiosis. The efficacy for a single BCA combining induced resistance with competition critically depended on application time; the efficacy was greatly reduced for delayed applications. The present study suggests that development of an effective strategy for BCA application is critically dependent upon our quantitative understanding of several key biocontrol processes and their interactions. Without reliable quantitative estimation of these processes, it is impossible to make quantitative predictions about biological control and hence to optimize BCA application strategies.
Identification of the Quantitative Trait Loci in Japonica Rice Landrace Heikezijing Responsible for Broad-Spectrum Resistance to Rice Blast
Authors: Shi Xiaoliang , Wang Jianfei , Bao Yongmei , Li Peifu , Xie Liujie , Huang Ji , Zhang Hongsheng
Published: July 2010

Rice blast is one of the most devastating diseases affecting rice production worldwide. One japonica landrace, Heikezijing, from the Taihu Lake area in China, has been reported to be highly resistant to most of the rice blast isolates collected from China and Japan. To effectively dissect the inheritance of its resistance, a population of recombinant inbred lines (RILs) (F2:8) was constructed from a cross between Heikezijing and Suyunuo, a blast-susceptible cultivar. Nineteen blast isolates from China and Japan were inoculated into 166 RILs and their parents, and 22 quantitative trait loci (QTLs) conferring resistance to these isolates were identified and mapped onto rice chromosomes 1, 7, 9, 11, and 12. Most of the QTLs conferred race-specific resistance to blast. Some QTLs, such as qtl11-5-5, conferred resistance to two or more isolates. One blast-resistant gene cluster, including qtl11-2-2, qtl11-3-1, qtl11-4-1, qtl11-5-5, qtl11-6-1, qtl11-7-5, qtl11-8-2, qtl11-9-2, qtl11-10-4, and qtl11-11-1, was found on the long arm of chromosome 11 in the japonica landrace. These loci offered effective resistance toward as many as 17 isolates, including 16 isolates from seven Chinese race groups and 1 isolate from Japan. The results from this study suggest that the Heikezijing landrace involves a number of genes that are associated with broad-spectrum resistance to rice blast.
Mealybug Transmission of Grapevine Leafroll Viruses: An Analysis of Virus–Vector Specificity
Authors: Tsai Chi-Wei , Rowhani Adib , Golino Deborah A. , Daane Kent M. , Almeida Rodrigo P. P.
Published: July 2010

To understand ecological factors mediating the spread of insect-borne plant pathogens, vector species for these pathogens need to be identified. Grapevine leafroll disease is caused by a complex of phylogenetically related closteroviruses, some of which are transmitted by insect vectors; however, the specificities of these complex virus–vector interactions are poorly understood thus far. Through biological assays and phylogenetic analyses, we studied the role of vector-pathogen specificity in the transmission of several grapevine leafroll-associated viruses (GLRaVs) by their mealybug vectors. Using plants with multiple virus infections, several virus species were screened for vector transmission by the mealybug species Planococcus ficus and Pseudococcus longispinus. We report that two GLRaVs (-4 and -9), for which no vector transmission evidence was available, are mealybug-borne. The analyses performed indicated no evidence of mealybug–GLRaV specificity; for example, different vector species transmitted GLRaV-3 and one vector species, Planococcus ficus, transmitted five GLRaVs. Based on available data, there is no compelling evidence of vector–virus specificity in the mealybug transmission of GLRaVs. However, more studies aimed at increasing the number of mealybug species tested as vectors of different GLRaVs are necessary. This is especially important given the increasing importance of grapevine leafroll disease spread by mealybugs in vineyards worldwide.
Polycistronic pre-mRNA processing in vitro: snRNP and pre-mRNA role reversal in trans-splicing
Authors: Lasda Erika L. , Allen Mary Ann , Blumenthal Thomas
Published: July 2010

Spliced leader (SL) trans-splicing in Caenorhabditis elegans attaches a 22-nucleotide (nt) exon onto the 5′ end of many mRNAs. A particular class of SL, SL2, splices mRNAs of downstream operon genes. Here we use an embryonic extract-based in vitro splicing system to show that SL2 specificity information is encoded within the polycistronic pre-mRNA, and that trans-splicing specificity is recapitulated in vitro. We define an RNA sequence required for SL2 trans-splicing, the U-rich (Ur) element, through mutational analysis and bioinformatics as a short stem–loop followed by a sequence motif, UAYYUU, located ∼50 nt upstream of the trans-splice site. Furthermore, this element is predicted in intercistronic regions of numerous operons of C. elegans and other species that use SL2 trans-splicing. We propose that the UAYYUU motif hybridizes with the 5′ splice site on the SL2 RNA to recruit the SL to the pre-mRNA. In this way, the UAYYUU motif in the pre-mRNA would serve an analogous function to the similar sequence in the U1 snRNA, which binds to the 5′ splice site of introns, effectively reversing the roles of snRNP and pre-mRNA in trans-splicing.
Antisense correction of SMN2 splicing in the CNS rescues necrosis in a type III SMA mouse model
Authors: Hua Yimin , Sahashi Kentaro , Hung Gene , Rigo Frank , Passini Marco A. , Bennett C. Frank , Krainer Adrian R.
Published: July 2010

Increasingsurvival of motor neuron 2, centromeric(SMN2) exon 7 inclusion to express more full-length SMN protein in motor neurons is a promising approach to treat spinal muscular atrophy (SMA), a genetic neurodegenerative disease. Previously, we identified a potent 2′-O-(2-methoxyethyl) (MOE) phosphorothioate-modified antisense oligonucleotide (ASO) that blocks anSMN2intronic splicing silencer element and efficiently promotes exon 7 inclusion in transgenic mouse peripheral tissues after systemic administration. Here we address its efficacy in the spinal cord—a prerequisite for disease treatment—and its ability to rescue a mild SMA mouse model that develops tail and ear necrosis, resembling the distal tissue necrosis reported in some SMA infants. Using a micro-osmotic pump, we directly infused the ASO into a lateral cerebral ventricle in adult mice expressing a humanSMN2transgene; the ASO gave a robust and long-lasting increase inSMN2exon 7 inclusion measured at both the mRNA and protein levels in spinal cord motor neurons. A single embryonic or neonatal intracerebroventricular ASO injection strikingly rescued the tail and ear necrosis in SMA mice. We conclude that this MOE ASO is a promising drug candidate for SMA therapy, and, more generally, that ASOs can be used to efficiently redirect alternative splicing of target genes in the CNS.
Successful Reproduction Requires the Function of Arabidopsis YELLOW STRIPE-LIKE1 and YELLOW STRIPE-LIKE3 Metal-Nicotianamine Transporters in Both Vegetative and Reproductive Structures
Authors: Chu Heng-Hsuan , Chiecko Jeff , Punshon Tracy , Lanzirotti Antonio , Lahner Brett , Salt David E. , Walker Elsbeth L.
Published: July 2010

Several members of the Yellow Stripe-Like (YSL) family of proteins are transporters of metals that are bound to the metal chelator nicotianamine or the related set of mugineic acid family chelators known as phytosiderophores. Here, we examine the physiological functions of three closely related Arabidopsis (Arabidopsis thaliana) YSL family members, AtYSL1, AtYSL2, and AtYSL3, to elucidate their role(s) in the allocation of metals into various organs of Arabidopsis. We show that AtYSL3 and AtYSL1 are localized to the plasma membrane and function as iron transporters in yeast functional complementation assays. By using inflorescence grafting, we show that AtYSL1 and AtYSL3 have dual roles in reproduction: their activity in the leaves is required for normal fertility and normal seed development, while activity in the inflorescences themselves is required for proper loading of metals into the seeds. We further demonstrate that the AtYSL1 and AtYSL2 proteins, when expressed from the AtYSL3 promoter, can only partially rescue the phenotypes of a ysl1ysl3 double mutant, suggesting that although these three YSL transporters are closely related and have similar patterns of expression, they have distinct activities in planta. In particular, neither AtYSL1 nor AtYSL2 is able to functionally complement the reproductive defects exhibited by ysl1ysl3 double mutant plants.
Plant Immunity Directly or Indirectly Restricts the Injection of Type III Effectors by the Pseudomonas syringae Type III Secretion System
Authors: Crabill Emerson , Joe Anna , Block Anna , van Rooyen Jennifer M. , Alfano James R.
Published: July 2010

Plants perceive microorganisms by recognizing microbial molecules known as pathogen-associated molecular patterns (PAMPs) inducing PAMP-triggered immunity (PTI) or by recognizing pathogen effectors inducing effector-triggered immunity (ETI). The hypersensitive response (HR), a programmed cell death response associated with ETI, is known to be inhibited by PTI. Here, we show that PTI-induced HR inhibition is due to direct or indirect restriction of the type III protein secretion system's (T3SS) ability to inject type III effectors (T3Es). We found that the Pseudomonas syringae T3SS was restricted in its ability to inject a T3E-adenylate cyclase (CyaA) injection reporter into PTI-induced tobacco (Nicotiana tabacum) cells. We confirmed this restriction with a direct injection assay that monitored the in planta processing of the AvrRpt2 T3E. Virulent P. syringae strains were able to overcome a PAMP pretreatment in tobacco or Arabidopsis (Arabidopsis thaliana) and continue to inject a T3E-CyaA reporter into host cells. In contrast, ETI-inducing P. syringae strains were unable to overcome PTI-induced injection restriction. A P. syringae pv tomato DC3000 mutant lacking about one-third of its T3E inventory was less capable of injecting into PTI-induced Arabidopsis plant cells, grew poorly in planta, and did not cause disease symptoms. PTI-induced transgenic Arabidopsis expressing the T3E HopAO1 or HopF2 allowed higher amounts of the T3E-CyaA reporter to be injected into plant cells compared to wild-type plants. Our results show that PTI-induced HR inhibition is due to direct or indirect restriction of T3E injection and that T3Es can relieve this restriction by suppressing PTI.
Homomeric Interaction of AtVSR1 Is Essential for Its Function as a Vacuolar Sorting Receptor
Authors: Kim Hyeran , Kang Hyangju , Jang Mihue , Chang Jeong Ho , Miao Yansong , Jiang Liwen , Hwang Inhwan
Published: July 2010

Vacuolar sorting receptors, BP80/VSRs, play a critical role in vacuolar trafficking of soluble proteins in plant cells. However, the mechanism of action of BP80 is not well understood. Here, we investigate the action mechanism of AtVSR1, a member of BP80 proteins in Arabidopsis (Arabidopsis thaliana), in vacuolar trafficking. AtVSR1 exists as multiple forms, including a high molecular mass homomeric complex in vivo. Both the transmembrane and carboxyl-terminal cytoplasmic domains of AtVSR1 are necessary for the homomeric interaction. The carboxyl-terminal cytoplasmic domain contains specific sequence information, whereas the transmembrane domain has a structural role in the homomeric interaction. In protoplasts, an AtVSR1 mutant, C2A, that contained alanine substitution of the region involved in the homomeric interaction, was defective in trafficking to the prevacuolar compartment and localized primarily to the trans-Golgi network. In addition, overexpression of C2A, but not wild-type AtVSR1, inhibited trafficking of soluble proteins to the vacuole and caused their secretion into the medium. Furthermore, C2A:hemagglutinin in transgenic plants interfered with the homomeric interaction of endogenous AtVSR1 and inhibited vacuolar trafficking of sporamin:green fluorescent protein. These data suggest that homomeric interaction of AtVSR1 is critical for its function as a vacuolar sorting receptor.
Phase I dose escalation and pharmacokinetic study of oral enzastaurin (LY317615) in advanced solid tumors
Authors: Mukohara Toru , Nagai Shunji , Koshiji Minori , Yoshizawa Kenichi , Minami Hironobu
Published: July 2010

Enzastaurin is an oral serine/threonine kinase inhibitor that targets the protein kinase C (PKC) and phosphoinositide 3‐kinase/AKT pathways to induce apoptosis and suppress proliferation of various cancer cell lines. This phase I study evaluated the tolerability and pharmacokinetics of enzastaurin in Japanese patients with advanced solid tumors and determined the recommended dose for phase II. Eligible patients had advanced solid tumors and an Eastern Cooperative Oncology Group performance status of 0–2. Patients received enzastaurin orally once daily until disease progression (PD) or unacceptable toxicity occurred. Enzastaurin was started at 250 mg/day followed by stepwise dose increases based on the incidence of dose‐limiting toxicities (DLT). Twenty‐three patients (seven patients: 250 mg; six patients: 375 mg; six patients: 500 mg; four patients: 750 mg) were enrolled and received enzastaurin. The major tumor types were non‐small‐cell lung cancer (n = 5) and breast cancer (n = 3). No DLT was reported at doses of 500 mg or less. Because two DLT (grade 2 QTc prolongation lasting for a week) were observed at 750 mg enzastaurin, this was determined as the maximum tolerated dose. Multiple daily doses at 500 mg achieved the target plasma concentration to inhibit PKC activity (1400 nmol/L). Enzastaurin was well tolerated up to 500 mg in Japanese patients with advanced solid tumors. The recommended dose for phase II was determined to be 500 mg daily for a 28‐day cycle on the basis of safety and plasma exposures. (Cancer Sci 2010);
Combination therapy of metronomic S‐1 dosing with oxaliplatin‐containing polyethylene glycol‐coated liposome improves antitumor activity in a murine colorectal tumor model
Authors: Doi Yusuke , Okada Tomoko , Matsumoto Haruna , Ichihara Masako , Ishida Tatsuhiro , Kiwada Hiroshi
Published: July 2010

Metronomic chemotherapy has been advocated recently as a novel chemotherapeutic regimen. Polyethylene glycol (PEG)‐coated liposomes are well known to accumulate in solid tumors by virtue of the highly permeable angiogenic blood vessels characteristic for growing tumor tissue, the so‐called “enhanced permeability and retention (EPR) effect”. To expand the range of applications and investigate the clinical value of the combination strategy, the therapeutic benefit of metronomic S‐1 dosing in combination with oxaliplatin (l‐OHP)‐containing PEG‐coated liposomes was evaluated in a murine colon carcinoma‐bearing mice model. S‐1 is an oral fluoropyrimidine formulation and metronomic S‐1 dosing is a promising alternative to infused 5‐FU in colorectal cancer therapy. Therefore, the combination of S‐1 with l‐OHP may be an alternative to FOLFOX (infusional 5‐FU/leucovorin (LV) in combination with l‐OHP), which is a first‐line therapeutic regimen of a colorectal carcinoma. The combination of oral metronomic S‐1 dosing with intravenous administration of liposomal l‐OHP formulation exerted excellent antitumor activity without severe overlapping side‐effects, compared with either metronomic S‐1 dosing, free l‐OHP or liposomal l‐OHP formulation alone or metronomic S‐1 dosing plus free l‐OHP. We confirmed that the synergistic antitumor effect is due to prolonged retention of l‐OHP in the tumor on account of the PEG‐coated liposomes, presumably via alteration of the tumor microenvironment caused by the metronomic S‐1 treatment. The combination regimen proposed here may be a breakthrough in treatment of intractable solid tumors and an alternative to FOLFOX in advanced colorectal cancer therapy with acceptable tolerance and preservation of quality of life (QOL). (Cancer Sci 2010; 101: 2470–2475)
Exposure to dogs is associated with a decreased tumour necrosis factor‐α‐producing capacity in early life
Authors: Lappalainen M. H. J. , Huttunen K. , Roponen M. , Remes S. , Hirvonen M.‐R. , Pekkanen J.
Published: July 2010

Background
It appears that contacts with furred animals early in life and already during gestation contribute to the immunological development in humans, but the mechanisms and relevant exposures are not clear.

Objective
To investigate whether exposure to animals during pregnancy and the first year of life is associated with early immune development, determined as stimulated cytokine responses of children at birth and at age 1 year.

Methods
Cord blood (n=228) and peripheral venous blood (n=200) samples 1 year after birth were collected and stimulated with Gram‐positive superantigen Staphylococcal enterotoxin B, Gram‐negative bacterial lipopolysaccharide (LPS) and the combination of mitogenic phorbol 12‐myristate 13‐acetate and calcium ionophore ionomycin (P/I) for 24 and 48 h. TNF‐α, IFN‐γ, IL‐5, IL‐8 and IL‐10 responses were measured by ELISA. For each cytokine, the time‐point with the highest response was chosen for further analyses. Animal contacts were surveyed by self‐administered questionnaires.

Results
Dog ownership was associated with decreased TNF‐α‐producing capacity at birth (P/I: median 841 vs. 881 pg/106 WBC, P=0.05) and 1 year after birth (P/I: 1290 vs. 1530, P=0.01; LPS: 425 vs. 508, P=0.02). Associations remained significant after adjustment for potential confounders. Cat ownership was not associated with cytokine production.

Conclusion
Having a dog in the household in infancy and already during pregnancy may be associated with reduced innate immune responses in early childhood. The observed attenuation of cytokine production may help in preventing exaggerated immune responses against harmless antigens later in life. Thus, intensive exposure to dogs in early life may be beneficial during normal immune maturation.

Cite this as: M. H. J. Lappalainen, K. Huttunen, M. Roponen, S. Remes, M.‐R. Hirvonen and J. Pekkanen, Clinical & Experimental Allergy, 2010 (40) 1498–1506.
Towards better prediction of seed dispersal by animals
Authors: Cousens Roger D. , Hill Julian , French Kris , Bishop Ian D.
Published: July 2010

1. Animals are the most important dispersal vector for a vast number of terrestrial plants.

2. Whereas our understanding of dispersal by wind has taken enormous conceptual strides in recent years, our ability to predict dispersal patterns by animals remains crude by comparison despite the large volume of research on this topic.

3. We review published models of dispersal by animals, discuss component processes that have been modelled in other contexts and indicate approaches that could usefully be taken in the future.

4. The current problem restricting progress is that few animal dispersal models include the processes most likely to cause dispersal to change over time or space. Thus, they are context‐specific, predicting only under the conditions from which data were collected.

5. The key to deeper understanding is to ask ‘What determines the behaviour of the vector; and what determines the influence of the vector on the trajectory of a seed’ (rather than what is the behaviour of the vector in a case study and how far does it move seeds in that study). This leads naturally to process‐based models with the ability to predict over a range of scenarios.

6. Priority processes for a more mechanistic approach include: animal movement within a landscape; linking gut throughput, defecation, feeding rate and other behaviours; and detachment from an animal’s surface. Models of gut throughput are probably already sufficient to include them in a dispersal model. Perhaps the best way to achieve progress would be to initiate an international working group of experts in modelling and the particular biological processes.
A renaissance in studies of ancient life
Authors: Schopf J. William , Kudryavtsev Anatoliy B.
Published: July 2010

In the Origin of Species, published a century‐and‐a‐half ago, Darwin was mystified by the lack of a ‘pre‐Cambrian’ fossil record, the existence of which he regarded as pivotal to his theory of evolution. For the next 100 years, this ‘missing’ fossil record—unknown and thought unknowable'stood out as arguably the single greatest blemish to Darwin's theory. Beginning in the 1950s, the answer to Darwin's problem began to be unearthed, a Precambrian record of flourishing communities of microscopic organisms now known to extend to 3500 million years ago. During recent years, studies of such ancient microbes have markedly increased, spurred by an influx of new workers and, especially, by the introduction of new analytical techniques, three of which are featured here: confocal laser scanning microscopy, and Raman‐spectral and fluorescence‐spectral imagery. Used together, these techniques provide evidence of the three‐dimensional form, cellular anatomy, and molecular structure of rock‐embedded microscopic fossils and of the minerals in which they are entombed that is unavailable by any other means.
Future atmospheric CO2 leads to delayed autumnal senescence
Authors: TAYLOR GAIL , TALLIS MATTHEW J. , GIARDINA CHRISTIAN P. , PERCY KEVIN E. , MIGLIETTA FRANCO , GUPTA POOJA S. , GIOLI BENIAMINO , CALFAPIETRA CARLO , GIELEN BIRGIT , KUBISKE MARK E. , SCARASCIA‐MUGNOZZA GIUSEPPE E. , KETS KATRE , LONG STEPHEN P. , KARNOSKY DAVID F.
Published: July 2010

Growing seasons are getting longer, a phenomenon partially explained by increasing global temperatures. Recent reports suggest that a strong correlation exists between warming and advances in spring phenology but that a weaker correlation is evident between warming and autumnal events implying that other factors may be influencing the timing of autumnal phenology. Using freely rooted, field‐grown Populus in two Free Air CO2 Enrichment Experiments (AspenFACE and PopFACE), we present evidence from two continents and over 2 years that increasing atmospheric CO2 acts directly to delay autumnal leaf coloration and leaf fall. In an atmosphere enriched in CO2 (by ∼45% of the current atmospheric concentration to 550 ppm) the end of season decline in canopy normalized difference vegetation index (NDVI) – a commonly used global index for vegetation greenness – was significantly delayed, indicating a greener autumnal canopy, relative to that in ambient CO2. This was supported by a significant delay in the decline of autumnal canopy leaf area index in elevated as compared with ambient CO2, and a significantly smaller decline in end of season leaf chlorophyll content. Leaf level photosynthetic activity and carbon uptake in elevated CO2 during the senescence period was also enhanced compared with ambient CO2. The findings reveal a direct effect of rising atmospheric CO2, independent of temperature in delaying autumnal senescence for Populus, an important deciduous forest tree with implications for forest productivity and adaptation to a future high CO2 world.
Revising a process‐based biogeochemistry model (DNDC) to simulate methane emission from rice paddy fields under various residue management and fertilizer regimes
Authors: FUMOTO TAMON , KOBAYASHI KAZUHIKO , LI CHANGSHENG , YAGI KAZUYUKI , HASEGAWA TOSHIHIRO
Published: July 2010

A comprehensive biogeochemistry model, DNDC, was revised to simulate crop growth and soil processes more explicitly and improve its ability to estimate methane (CH4) emission from rice paddy fields under a wide range of climatic and agronomic conditions. The revised model simulates rice growth by tracking photosynthesis, respiration, C allocation, tillering, and release of organic C and O2 from roots. For anaerobic soil processes, it quantifies the production of electron donors [H2 and dissolved organic carbon (DOC)] by decomposition and rice root exudation, and simulates CH4 production and other reductive reactions based on the availability of electron donors and acceptors (NO3−, Mn4+, Fe3+, and SO42−). Methane emission through rice is simulated by a diffusion routine based on the conductance of tillers and the CH4 concentration in soil water. The revised DNDC was tested against observations at three rice paddy sites in Japan and China with varying rice residue management and fertilization, and produced estimates consistent with observations for the variation in CH4 emission as a function of residue management. It also successfully predicted the negative effect of (NH4)2SO4 on CH4 emission, which the current model missed. Predicted CH4 emission was highly sensitive to the content of reducible soil Fe3+, which is the dominant electron acceptor in anaerobic soils. The revised DNDC generally gave acceptable predictions of seasonal CH4 emission, but not of daily CH4 fluxes, suggesting the model's immaturity in describing soil heterogeneity or rice cultivar‐specific characteristics of CH4 transport. It also overestimated CH4 emission at one site in a year with low temperatures, suggesting uncertainty in root biomass estimates due to the model's failure to consider the temperature dependence of leaf area development. Nevertheless, the revised DNDC explicitly reflects the effects of soil electron donors and acceptors, and can be used to quantitatively estimate CH4 emissions from rice fields under a range of conditions.
Comparison of phenology trends by land cover class: a case study in the Great Basin, USA
Authors: BRADLEY BETHANY A. , MUSTARD JOHN F.
Published: July 2010

Direct impacts of human land use and indirect impacts of anthropogenic climate change may alter land cover and associated ecosystem function, affecting ecological goods and services. Considerable work has been done to identify long‐term global trends in vegetation greenness, which is associated with primary productivity, using remote sensing. Trend analysis of satellite observations is subject to error, and ecosystem change can be confused with interannual variability. However, the relative trends of land cover classes may hold clues about differential ecosystem response to environmental forcing. Our aim was to identify phenological variability and 10‐year trends for the major land cover classes in the Great Basin. This case study involved two steps: a regional, phenology‐based land cover classification and an identification of phenological variability and 10‐year trends stratified by land cover class. The analysis used a 10‐year time series of Advanced Very High Resolution Radiometer satellite data to assess regional scale land cover variability and identify change. The phenology‐based regional classification was more detailed and accurate than national or global products. Phenological variability over the 10‐year period was high, with substantial shifts in timing of start of season of up to 9 weeks. The mean long‐term trends of montane land cover classes were significantly different from valley land cover classes due to a poor response of montane shrubland and pinyon‐juniper woodland to the early 1990s drought. The differential response during the 1990s suggests that valley ecosystems may be more resilient and montane ecosystems more susceptible to prolonged drought. This type of regional‐scale land cover analysis is necessary to characterize current patterns of land cover phenology, distinguish between anthropogenically driven land cover change and interannual variability, and identify ecosystems potentially susceptible to regional and global change.
Effects of climate on population fluctuations of ibex
Authors: GRØTAN VIDAR , SÆTHER BERNT‐ERIK , FILLI FLURIN , ENGEN STEINAR
Published: July 2010

Predicting the effects of the expected changes in climate on the dynamics of populations require that critical periods for climate‐induced changes in population size are identified. Based on time series analyses of 26 Swiss ibex (Capra ibex) populations, we show that variation in winter climate affected the annual changes in population size of most of the populations after accounting for the effects of density dependence and demographic stochasticity. In addition, precipitation during early summer also influenced the population fluctuations. This suggests that the major influences of climate on ibex population dynamics operated either through loss of individuals during winter or early summer, or through an effect on fecundity. However, spatial covariation in these climate variables was not able to synchronize the population fluctuations of ibex over larger distances, probably due to large spatial heterogeneity in the effects of single climate variables on different populations. Such spatial variation in the influence of the same climate variable on the local population dynamics suggests that predictions of influences of climate change need to account for local differences in population dynamical responses to climatic conditions.
Infrared heater arrays for warming ecosystem field plots
Authors: KIMBALL BRUCE A. , CONLEY MATTHEW M. , WANG SHIPING , LIN XINGWU , LUO CAIYUN , MORGAN JACK , SMITH DAVID
Published: July 2010

There is a need for methodology to warm open‐field plots in order to study the likely effects of global warming on ecosystems in the future. Herein, we describe the development of arrays of more powerful and efficient infrared heaters with ceramic heating elements. By tilting the heaters at 45° from horizontal and combining six of them in a hexagonal array, good uniformity of warming was achieved across 3‐m‐diameter plots. Moreover, there do not appear to be obstacles (other than financial) to scaling to larger plots. The efficiency [ηh (%); thermal radiation out per electrical energy in] of these heaters was higher than that of the heaters used in most previous infrared heater experiments and can be described by: ηh= 10 + 25exp(− 0.17 u), where u is wind speed at 2 m height (m s− 1). Graphs are presented to estimate operating costs from degrees of warming, two types of plant canopy, and site windiness. Four such arrays were deployed over plots of grass at Haibei, Qinghai, China and another at Cheyenne, Wyoming, USA, along with corresponding reference plots with dummy heaters. Proportional integral derivative systems with infrared thermometers to sense canopy temperatures of the heated and reference plots were used to control the heater outputs. Over month‐long periods at both sites, about 75% of canopy temperature observations were within 0.5 °C of the set‐point temperature differences between heated and reference plots. Electrical power consumption per 3‐m‐diameter plot averaged 58 and 80 kW h day− 1 for Haibei and Cheyenne, respectively. However, the desired temperature differences were set lower at Haibei (1.2 °C daytime, 1.7 °C night) than Cheyenne (1.5 °C daytime, 3.0 °C night), and Cheyenne is a windier site. Thus, we conclude that these hexagonal arrays of ceramic infrared heaters can be a successful temperature free‐air‐controlled enhancement (T‐FACE) system for warming ecosystem field plots.
Climatic connectivity between Africa and Europe may serve as a basis for phenotypic adjustment of migration schedules of trans‐Saharan migratory birds
Authors: SAINO NICOLA , AMBROSINI ROBERTO
Published: July 2010

Most European migratory birds wintering in sub‐Saharan Africa have anticipated arrival to the breeding areas over the past decades. This phenological change may be ultimately caused by warming of the Northern Hemisphere via evolutionary changes or phenotypic plasticity in migration behavior. First arrival dates are negatively predicted by temperatures upon arrival to the breeding grounds. This seems puzzling, because migrants should be unable to predict weather conditions at long range. Migrants can enjoy diverse fitness benefits from early arriving. However, if weather conditions at destination cannot be predicted, early arrival can also entail severe costs. If meteorological conditions in Europe during breeding covary with those in sub‐Saharan Africa during late winter, long‐distance migrants may have a clue to predict meteorological conditions in their breeding areas while they are still in Africa and adjust their migration schedule consequently, an idea that has never been tested. We analyzed the correlation between March–April temperature anomalies (Tan) in Europe and FebruaryTanin the Sahel and sub‐Sahel, where long‐distance migrants winter or stop‐over.Tanin Africa negatively predictedTanin Europe, the association being particularly strong (unsigned effect size,zr>0.35) for eastern Sahel and northern and eastern Europe, where the risks of early arrival may be larger. However, the strength of the correlations betweenTanin the two continents has declined during the last 25 years; thus, possibly, partly compromising adaptive mechanisms of adjustment of migration. The existence of such climatic connectivity leads to several predictions, including that positiveTanin Africa should delay arrival. Consistent with this prediction, we found that first arrival dates of seven long‐distance migratory species positively covaried with FebruaryTanin Africa. Thus, while wintering, migrants might be able to predict meteorological conditions at the beginning of the breeding season, and phenotypically adjust migration schedules to optimally tune arrival date.
Combined statistical and dynamical assessment of simulated vegetation–rainfall interactions in North Africa during the mid‐Holocene1
Authors: NOTARO MICHAEL , WANG YI , LIU ZHENGYU , GALLIMORE ROBERT , LEVIS SAMUEL
Published: July 2010

A negative feedback of vegetation cover on subsequent annual precipitation is simulated for the mid‐Holocene over North Africa using a fully coupled general circulation model with dynamic vegetation, FOAM‐LPJ (Fast Ocean Atmosphere Model‐Lund Potsdam Jena Model). By computing a vegetation feedback parameter based on lagged auto‐covariances, the simulated impact of North African vegetation on precipitation is statistically quantified. The feedback is also dynamically assessed through initial value ensemble experiments, in which North African grass cover is initially reduced and the climatic response analyzed. The statistical and dynamical assessments of the negative vegetation feedback agree in sign and relative magnitude for FOAM‐LPJ. The negative feedback on annual precipitation largely results from a competition between bare soil evaporation and plant transpiration, with increases in the former outweighing reductions in the latter given reduced grass cover. This negative feedback weakens and eventually reverses sign over time during a transient simulation from the mid‐Holocene to present. A similar, but weaker, negative feedback is identified in Community Climate System Model Version 2 (CCSM2) over North Africa for the mid‐Holocene.
Phosphorus inputs unmask negative effects of ultraviolet radiation on algae in a high mountain lake
Authors: CARRILLO P. , DELGADO‐MOLINA J. A. , MEDINA‐SÁNCHEZ J. M. , BULLEJOS F. J. , VILLAR‐ARGAIZ M.
Published: July 2010

Ultraviolet solar radiation (UVR) and atmospheric nutrient loads to pristine ecosystems are global climate change phenomena that simultaneously affect aquatic organisms in ways not easily predicted by single factor studies. Plankton in a high mountain lake was exposed in situ to increasing phosphorus (P) concentrations (mimicking atmospheric pulses) in absence or presence of UVR in order to identify their interactive effect on functional [primary production, organic carbon (C) release (EOC), and percentage of C released (%EOC)], growth rate, structural–physiological (algal biomass, sestonic C, P content, chlorophyll a (Chl a), and Chl a : C ratio, P cell quota, cell‐specific Chl a), and stoichiometric (autotroph C : P ratio) traits. The availability of P after the pulse determined the intensity of responses by primary producers to UVR stress. All structural–physiological and functional variables significantly increased by up to two orders of magnitude in response to P enrichment. UV radiation, over a long‐term scale, exerted significant deleterious effects on most structural–physiological variables when inorganic P was added at high levels (≥30 μg P L−1). The subsequent unexpected negative synergistic UVR × P effect on algal development did not support our initial hypothesis that P input might buffer the harmful UVR effect. UVR exerted a weak negative effect on primary production but strongly enhanced the absolute and percentage excretion of C (up to 60%), mechanism responsible of a significant reduction in autotroph C : P ratios. We propose that low sestonic C : P ratios are the outcome of an adaptive strategy of algae in environments with high UVR exposure and extreme nutrient limitation and have important implications for C flux through grazing vs. microbial food webs in oligotrophic systems.
Getting biodiversity intactness indices right: ensuring that ‘biodiversity’ reflects ‘diversity’
Authors: FAITH D. P. , FERRIER S. , WILLIAMS K. J.
Published: July 2010

The 2010 biodiversity target of a ‘significant reduction in the current rate of biodiversity loss’ presents challenges for effective measurement of changes in global/regional biodiversity. A simple ‘biodiversity intactness index’ (BII) is attractive in using available data and expert opinion, but is seen to be only weakly linked to ‘biodiversity’ in its usual sense of ‘variation’. An example illustrates how an improved BII score could result even when there are large species losses. A family of alternative biodiversity ‘representativeness indices’ better reflect variation. They use the same readily available information, plus simple species–area relationships (SAR) and genetic diversity curves. A new genetic‐diversity abundance‐fraction curve, like SAR, is linear in log–log space. The new representativeness indices incorporate, through range‐abundance curves, the abundance fraction estimates normally used for BII. Land use or climate change impacts therefore can reflect partial rather than total biodiversity losses at localities. Estimates of biodiversity gains/losses using these indices enable a novel regional planning‐based approach for addressing the 2010 target.
Nitrogen addition reduces soil respiration in a mature tropical forest in southern China
Authors: MO JIANGMING , ZHANG WEI , ZHU WEIXING , GUNDERSEN PER , FANG YUNTING , LI DEJUN , WANG HUI
Published: July 2010

Response of soil respiration (CO2 emission) to simulated nitrogen (N) deposition in a mature tropical forest in southern China was studied from October 2005 to September 2006. The objective was to test the hypothesis that N addition would reduce soil respiration in N saturated tropical forests. Static chamber and gas chromatography techniques were used to quantify the soil respiration, following four‐levels of N treatments (Control, no N addition; Low‐N, 5 g N m−2 yr−1; Medium‐N, 10 g N m−2 yr−1; and High‐N, 15 g N m−2 yr−1 experimental inputs), which had been applied for 26 months before and continued throughout the respiration measurement period. Results showed that soil respiration exhibited a strong seasonal pattern, with the highest rates found in the warm and wet growing season (April–September) and the lowest rates in the dry dormant season (December–February). Soil respiration rates showed a significant positive exponential relationship with soil temperature, whereas soil moisture only affect soil respiration at dry conditions in the dormant season. Annual accumulative soil respiration was 601±30 g CO2‐C m−2 yr−1 in the Controls. Annual mean soil respiration rate in the Control, Low‐N and Medium‐N treatments (69±3, 72±3 and 63±1 mg CO2‐C m−2 h−1, respectively) did not differ significantly, whereas it was 14% lower in the High‐N treatment (58±3 mg CO2‐C m−2 h−1) compared with the Control treatment, also the temperature sensitivity of respiration, Q10 was reduced from 2.6 in the Control with 2.2 in the High‐N treatment. The decrease in soil respiration occurred in the warm and wet growing season and were correlated with a decrease in soil microbial activities and in fine root biomass in the N‐treated plots. Our results suggest that response of soil respiration to atmospheric N deposition in tropical forests is a decline, but it may vary depending on the rate of N deposition.
Effect of natural antioxidants on stored freeze‐dried food product formulated using horse mackerel (Trachurus trachurus)
Authors: Sarkardei Samiramis , Howell Nazlin K.
Published: July 2010

The physical and chemical properties of Trachurus trachurus (horse mackerel) as well as a food product in the presence and absence of natural antioxidants, were investigated. The rate of lipid oxidation in the freeze‐dried horse mackerel product stored at room temperature (22 °C) was investigated, using peroxide value (PV), thiobarbituric acid reactive substances (TBARS) and hexanal concentration to determine primary, secondary and tertiary oxidation products. Natural antioxidants were used to slow down oxidation processes and to improve nutritional and eating quality. These included vitamin E + vitamin C + citric acid (250, 250, 100 mg kg−1, respectively), vitamin E + vitamin C + citric acid + rosemary (250, 250, 100, 250 mg kg−1, respectively) and rosemary (250 mg kg−1). Biochemical analysis such as PV and TBARS measurements showed that the combination of vitamin E + vitamin C + citric acid (250, 250, 100 mg kg−1) were found to be the most significant (P ≤ 0.01) in controlling the rate of lipid oxidation in freeze‐dried food followed by rosemary (250 mg kg−1). There was an initial rise in the PV of all samples, which dropped after 8 weeks, because of formation of secondary oxidation products. The rise in PV was much higher in the control samples with no antioxidants added, compared with the antioxidant‐treated samples. Combinations of E + C + citric acid treatment group followed by rosemary alone were the most significant in lowering PV, hence, reducing formation of primary oxidation products (P ≤ 0.01). Once the primary oxidation products were lowered, TBARS levels (secondary oxidation products) increased in control samples after 12 weeks; however, in E + C + citric acid treatment group and rosemary‐treated samples, this increase was significantly lower (P ≤ 0.01). There was a rise in hexanal concentration for up to 8 weeks, which dropped only in the antioxidant‐treated groups and continued to rise in the control samples.