Constant High Level Research Articles

Light–dark duration alternation effects on Rhodobacter sphaeroides growth, membrane properties and bio-hydrogen production in batch culture

The effects of light–dark duration alternation on bacterial growth and hydrogen (H2) production performance of Rhodobacter sphaeroides MDC 6522 from Armenian mineral springs were firstly investigated in batch culture. Five types of light–dark duration were applied: 1st culture was illuminated continuously (control); 2nd and 3rd cultures were illuminated after inoculation during 24–48 h, then dark conditions were applied; 4th and 5th cultures were illuminated after 24–48 h dark period. R. sphaeroides did not grow well in the dark conditions, but growth and H2 production were restored upon illumination. When culture was illuminated after 24 h dark period, H2 yield was maintained at a constant high level during 96–144 h, and duration of photo-fermentation was delayed up to 144 h, compared to the control. When culture was illuminated till H2 production started (48 h), and then dark conditions were applied, H2 production ability of R. sphaeroides persisted during the growth up to 120 h, whereas in the control cells H2 production was not observed. Moreover, the results indicated that light–dark alternation affected the formation of photosynthetic pigments and membrane H+ conductance. This study is of significant for understanding of bacterial metabolism regulation mechanisms and for application of purple bacteria in H2 production biotechnology.

Type 1 diabetes alters astrocytic properties related with neurotransmitter supply, causing abnormal neuronal activities

Glutamine synthetase (GS), an astrocytic protein in the brain, mediates the process by which glutamate (Glu) is transformed into glutamine (Gln) during Glu and gamma-aminobutyric acid (GABA) de novo synthesis. There are many types of neural complications related with those neurotransmitters in type 1 diabetes (T1D) patients, but there is little information about the change GS. Therefore, we examined changes in GS activity and expression, as well as the amount of Glu, Gln, and GABA in the brain of a T1D animal model. Using primary culture we found that glucose fluctuation caused glial fibrillary acidic protein (GFAP) and GS changes but constant high glucose level didn׳t. In T1D mouse, GS expression increased in the prefrontal cortex (PFC) and hippocampus (HI), but decreased GS activity was only observed in the HI whereas GFAP expression decreased in both regions. Gln increased in both regions, but Glu and GABA were only increased in the HI of T1D animals where GS activity decreased with higher reactive oxygen/nitrogen species. Collectively, low GS activity may be closely related with high levels of Glu and GABA in the HI of T1D brain, and this would result in abnormal neurotransmissions.

浙江丽水中华大蟾蜍和黑眶蟾蜍蝌蚪对水位变化的表型响应

PDF HTML阅读 XML下载 导出引用 引用提醒 浙江丽水中华大蟾蜍和黑眶蟾蜍蝌蚪对水位变化的表型响应 DOI: 10.5846/stxb201404280845 作者: 作者单位: 丽水学院生态学院,丽水学院生态学院,丽水学院生态学院,丽水学院生态学院,丽水学院生态学院,丽水学院生态学院,丽水学院生态学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目(31270443, 30970435); 浙江省大学生科技创新活动计划(2012R429022) Phenotypic responses to water level change in Bufo gargarizans and Duttaphrynus melanosticus tadpoles at Lishui, Zhejiang Author: Affiliation: College of Ecology,Lishui University,College of Ecology,Lishui University,College of Ecology,Lishui University,College of Ecology,Lishui University,College of Ecology,Lishui University,College of Ecology,Lishui University,College of Ecology,Lishui University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:全球气候变暖引发栖息地干涸将对生活在水中的无尾类幼体提出了挑战。通过浙江丽水中华大蟾蜍(Bufo gargarizans)和黑眶蟾蜍(Duttaphrynus melanosticus)蝌蚪在实验条件下对不同水位变化的表型响应,检测表型可塑性的遗传性和环境近因性影响。结果表明,水位变化对中华大蟾蜍蝌蚪早期发育历期、头宽和体重影响不显著,对体长影响显著,其中逐减水位最大、恒低水位最小,慢波、恒高与快波、逐增水位依次减少;水位变化对黑眶蟾蜍蝌蚪早期发育历期、体长、头宽和体重影响均显著;发育历期以恒高水位最大,恒低水位最小;体长以逐减水位最大,恒低、快波和慢波水位显著偏小,逐增和快波水位居中;头宽以恒低水位最小,逐增水位居中,其余较大;体重以恒低水位最小、恒高水位最大,其余居中。水位变化对中华大蟾蜍蝌蚪的变态时间、体长、头宽和体重影响均不显著;水位变化对黑眶蟾蜍蝌蚪的变态时间、体长和体重影响均显著,对头宽影响不显著;恒低水位的变态时间最长,恒高水位的变态时间最短,其他水位变化之间差异不显著;恒高水位的体长最大,恒低和快波水位最小,其他居中;逐增和快波水位的体重最大,恒低水位最小。研究结果表明,繁殖季节不同的中华大蟾蜍和黑眶蟾蜍蝌蚪响应水位变化的表型可塑性差异显著,长期在容易发生干旱和水位变化的冬季繁殖的中华大蟾蜍蝌蚪的表型可塑性低,在雨水充沛的春季繁殖的黑眶蟾蜍蝌蚪的表型可塑性高,表现出表型可塑性的种间差异和遗传性;在早期发育过程中,两种蝌蚪体长的共同的表型变异与缺乏遗传基础的环境近因性影响有关;黑眶蟾蜍蝌蚪对低水位或水位下降作出减速分化的消极响应,响应程度与环境信号的强弱直接相关。 Abstract:Habitat drying caused by global warming will raise a challenge for anuran larvae living in water. We investigated the phenotypic response to six different patterns of water level change in Bufo gargarizans and Duttaphrynus melanosticus tadpoles under laboratory conditions. The aim of this study was to examine the heritable basis and environmental proximate causes of phenotypic plasticity of these two species tadpoles. The results showed that all the six water level treatments had no significant effect on the early development Gosner stage (GS), head width (HW), or body mass (BM) of B. gargarizans tadpoles on the 14th day, but there was a significant effect on their snout-vent length (SVL). The SVL of B. gargarizans tadpoles raised in decreasing water levels were the longest, while the ones raised in constant low water levels had the shortest SVL than the remaining groups. Conversely, the six water level treatments had respectively significant effects on the GS, SVL, HW and BM of D. melanosticus tadpoles on the same day, respectively. Firstly, those tadpoles raised in constant high water level developed most fast, while the ones raised in constant low water level developed most slowly. Secondly, the tadpoles raised in decreasing water level had greater SVL, while the ones raised in constant low, fast fluctuation and slow fluctuation water levels had smaller SVL than the remaining groups. Thirdly, HW of the tadpoles raised in constant low water levels was the narrowest, followed by the ones raised in increasing water levels, the others raised in the remaining water level groups had the biggest HW. Lastly, BM of tadpoles in constant low water levels was the smallest, while the ones raised in constant high water level had heavier BM than the remaining groups. The water level treatments had no significant effect on the time of metamorphosis and body size at metamorphosis including SVL, HW, and BM in B. gargarizan. However, there were significant effects of the water level changes on the time of metamorphosis and body size at metamorphosis including SVL and BM, except for HW, in D. melanosticus. Tadpoles raised in the constant low water levels had protracted metamorphosis, whereas the tadpoles raised under the constant high water levels had shortened metamorphosis. SVL at metamorphosis of D. melanosticus in the constant high water levels was the largest, while the ones raised in constant low and rapidly fluctuating water levels were the shortest. BM at metamorphosis of D. melanosticus raised in the increasing and rapidly fluctuating water levels were the biggest, while the ones raised in the constant low water levels were the smallest. Our results suggest that there are significant interspecific differences in the phenotypic plasticity respond to desiccation risks between B. gargarizans and D. melanosticus tadpoles: the former was weaker than the latter. Winter-breeder B. gargarizans tadpoles experienced habitat drying more frequently, while spring-breeder D. melanosticus tadpoles experienced habitat drying rarely. This showed the interspecific differences and hereditary of the phenotypic plasticity. During the early development of the two toad tadpoles, the common phenotypic variations in their SVL were associated with lack of genetic basis of environmental proximate causes. The response to constant low or decreasing water level in D. melanosticus tadpoles was negative (deceleration of differentiation), and the response degree was directly related to the strength of the environmental signals. 参考文献 相似文献 引证文献

Instrumentational complexity of music genres and why simplicity sells.

Listening habits are strongly influenced by two opposing aspects, the desire for variety and the demand for uniformity in music. In this work we quantify these two notions in terms of instrumentation and production technologies that are typically involved in crafting popular music. We assign an ‘instrumentational complexity value’ to each music style. Styles of low instrumentational complexity tend to have generic instrumentations that can also be found in many other styles. Styles of high complexity, on the other hand, are characterized by a large variety of instruments that can only be found in a small number of other styles. To model these results we propose a simple stochastic model that explicitly takes the capabilities of artists into account. We find empirical evidence that individual styles show dramatic changes in their instrumentational complexity over the last fifty years. ‘New wave’ or ‘disco’ quickly climbed towards higher complexity in the 70s and fell back to low complexity levels shortly afterwards, whereas styles like ‘folk rock’ remained at constant high instrumentational complexity levels. We show that changes in the instrumentational complexity of a style are related to its number of sales and to the number of artists contributing to that style. As a style attracts a growing number of artists, its instrumentational variety usually increases. At the same time the instrumentational uniformity of a style decreases, i.e. a unique stylistic and increasingly complex expression pattern emerges. In contrast, album sales of a given style typically increase with decreasing instrumentational complexity. This can be interpreted as music becoming increasingly formulaic in terms of instrumentation once commercial or mainstream success sets in.

Role of Mitochondrial Calcium Uniporter in Early Brain Injury After Experimental Subarachnoid Hemorrhage.

Previous studies have shown that mitochondrial Ca(2+) is undertaken by mitochondrial calcium uniporter (MCU), and its accumulation is associated with the development of many diseases. However, little was known about the role of MCU in early brain injury (EBI) after subarachnoid hemorrhage (SAH). MCU can be opened by spermine under a physiological condition and inhibited by ruthenium red (RR). Herein, we investigated the effects of RR and spermine to reveal the role of MCU in SAH animal model. The data obtained with biochemical and histological assays showed that mitochondrial Ca(2+) concentration was significantly increased in the temporal cortex of rats 1, 2, and 3 days after SAH, consistent with constant high levels of cellular Ca(2+) concentration. In agreement with the observation in the acute phase, SAH rats showed an obvious increase of reactive oxygen species (ROS) level and decrease of ATP production. Blockage of MCU prevented Ca(2+) accumulation, abated the level of oxidative stress, and improved the energy supply. Translocation of cytochrome c, increased cleaved caspase-3, and a large amount of apoptotic cells after SAH were reversed by RR administration. Surprisingly, exogenous spermine did not increase cellular Ca(2+) concentration, but lessened the Ca(2+) accumulation after SAH to benefit the rats. Taken together, our results demonstrated that blockage of MCU or prevention of Ca(2+) accumulation after SAH is essential in EBI after SAH. These findings suggest that MCU is considered to be a therapeutic target for patients suffering from SAH.

Farmers without borders-genetic structuring in century old barley (Hordeum vulgare).

The geographic distribution of genetic diversity can reveal the evolutionary history of a species. For crop plants, phylogeographic patterns also indicate how seed has been exchanged and spread in agrarian communities. Such patterns are, however, easily blurred by the intense seed trade, plant improvement and even genebank conservation during the twentieth century, and discerning fine-scale phylogeographic patterns is thus particularly challenging. Using historical crop specimens, these problems are circumvented and we show here how high-throughput genotyping of historical nineteenth century crop specimens can reveal detailed geographic population structure. Thirty-one historical and nine extant accessions of North European landrace barley (Hordeum vulgare L.), in total 231 individuals, were genotyped on a 384 single nucleotide polymorphism assay. The historical material shows constant high levels of within-accession diversity, whereas the extant accessions show more varying levels of diversity and a higher degree of total genotype sharing. Structure, discriminant analysis of principal components and principal component analysis cluster the accessions in latitudinal groups across country borders in Finland, Norway and Sweden. FST statistics indicate strong differentiation between accessions from southern Fennoscandia and accessions from central or northern Fennoscandia, and less differentiation between central and northern accessions. These findings are discussed in the context of contrasting historical records on intense within-country south to north seed movement. Our results suggest that although seeds were traded long distances, long-term cultivation has instead been of locally available, possibly better adapted, genotypes.

Block copolymer/homopolymer dual-layer hollow fiber membranes

We manufactured the first time block copolymer dual-layer hollow fiber membranes and dual layer flat sheet membranes manufactured by double solution casting and phase inversion in water. The support porous layer was based on polystyrene and the selective layer with isopores was formed by micelle assembly of polystyrene-b-poly-4-vinyl pyridine. The dual layers had an excellent interfacial adhesion and pore interconnectivity. The dual membranes showed pH response behavior like single layer block copolymer membranes with a low flux for pH values less than 3, a fast increase between pH4 and pH6 and a constant high flux level for pH values above 7. The dry/wet spinning process was optimized to produce dual layer hollow fiber membranes with polystyrene internal support layer and a shell block copolymer selective layer.

Bed-To-Wall Heat Transfer in a Supercritical Circulating Fluidised Bed Boiler

Abstract The purpose of this work is to find a correlation for heat transfer to walls in a 1296 t/h supercritical circulating fluidised bed (CFB) boiler. The effect of bed-to-wall heat transfer coefficient in a long active heat transfer surface was discussed, excluding the radiation component. Experiments for four different unit loads (i.e. 100% MCR, 80% MCR, 60% MCR and 40% MCR) were conducted at a constant excess air ratio and high level of bed pressure (ca. 6 kPa) in each test run. The empirical correlation of the heat transfer coefficient in a large-scale CFB boiler was mainly determined by two key operating parameters, suspension density and bed temperature. Furthermore, data processing was used in order to develop empirical correlation ranges between 3.05 to 5.35 m·s-1 for gas superficial velocity, 0.25 to 0.51 for the ratio of the secondary to the primary air, 1028 to 1137K for bed temperature inside the furnace chamber of a commercial CFB boiler, and 1.20 to 553 kg·m-3 for suspension density. The suspension density was specified on the base of pressure measurements inside the boiler’s combustion chamber using pressure sensors. Pressure measurements were collected at the measuring ports situated on the front wall of the combustion chamber. The obtained correlation of the heat transfer coefficient is in agreement with the data obtained from typical industrial CFB boilers.

Effects of hydroperiod duration on developmental plasticity in tiger frog (Hoplobatrachus chinensis) tadpoles.

While developmental plasticity can facilitate evolutionary diversification of organisms, the effects of water levels as an environmental pressure on tiger frogs remains unclear. This study clarifies the relationship by studying the responses of tiger frog (Hoplobatrachus chinensis) tadpoles to simulated hydroperiods (i.e., constant low water levels, constant high water levels, increasing water levels, decreasing water levels, rapid changes in water levels and gradual fluctuations in water levels) in a laboratory setting. ANOVA analysis showed that none of the water level treatments had any significant effect on the total length, body mass, or developmental stages of H. chinensis tadpoles half way through development (11 days old). Tadpoles raised in rapidly fluctuating water levels had protracted metamorphosis, whereas tadpoles raised under low and gradually fluctuating water levels had shortened metamorphosis. None of the water level treatments had a significant effect on the snout-vent length (SVL) or body mass of H. chinensis tadpoles at Gosner stage 42, or on the body mass of tadpoles at Gosner stage 45. However, the tadpoles raised in high levels and rapidly fluctuating water levels, significantly larger SVL at Gosner stage 45, while ones under gradually fluctuating water levels had smaller SVL than the other groups. Time to metamorphosis was positively correlated with body size (SVL) at metamorphosis in H. chinensis tadpoles. H. chinensis tadpoles under constant low water level had the highest mortality rate among all the treatments (G-test). Moreover, ANOVA and ACNOVA (with body length as the covariate) indicated that water levels had no significant effect on either the morphology (i.e. head length, head width, forelimb length, hindlimb length and body width) or the jumping ability of juvenile H. chinensis. These results suggest that the observed accelerated metamorphosis and high mortality of H. chinensis tadpoles under decreasing water level treatment was driven by density-induced physical interactions among increasing conspecifics.

Constant high adrenal FDG uptake in PET/CT associated with mitochondrial disease

We describe a patient with the m.3243A>G mitochondrial DNA mutation who developed sepsis caused by Streptococcus constellatus. In the acute phase of illness, abnormally high uptake of (18)F-FDG was observed in both adrenal glands that appeared anatomically normal. In repeated imaging six months later the adrenal uptake had diminished but remained clearly elevated. We did not observe high adrenal FDG uptake as in the patient described here among 30 patients with Staphylococcus aureus sepsis that were investigated with identical imaging protocol. In sepsis, oxygen consumption and metabolic rate are increased compared to normal metabolism. The observed high adrenal FDG uptake during sepsis in this patient probably reflects the acute metabolic stress induced by the infection. Interestingly, in repeated imaging six months later, the adrenal SUVs had diminished but were still abnormally high: this suggests constant high levels of metabolic stress associated with the mitochondrial disorder.

Rapid changes in arousal states of healthy volunteers during robot-assisted gait training: a quantitative time-series electroencephalography study.

BackgroundRobot-assisted gait training (RAGT) is expected to be an effective rehabilitative intervention for patients with gait disturbances. However, the monotonous gait pattern provided by robotic guidance tends to induce sleepiness, and the resultant decreased arousal during RAGT may negatively affect gait training progress. This study assessed electroencephalography (EEG)-based, objective sleepiness during RAGT and examined whether verbal or nonverbal warning sounds are effective stimuli for counteracting such sleepiness.MethodsTwelve healthy men walked on a treadmill for 6 min, while being guided by a Gait-Assistance Robot, under 3 experimental conditions: with sine-wave sound stimulation (SS), verbal sound stimulation (VS), and no sound stimulation (NS). The volunteers were provided with warning sound stimulation at 4 min (ST1), 4 min 20 s (ST2), 4 min 40 s (ST3), and 5 min (ST4) after the start of RAGT. EEGs were recorded at the central (Cz) and occipital (O1 and O2) regions (International 10–20 system) before and during RAGT, and 4-s segments of EEG data were extracted from the filtered data during the 8 experimental periods: middle of the eyes-closed condition; middle of the eyes-open condition; beginning of RAGT; immediately before ST1; immediately after ST1, ST2, ST3, and ST4. According to the method used in the Karolinska drowsiness test, the power densities of the theta, alpha 1, and alpha 2 bands were calculated as indices of objective sleepiness.ResultsComparisons of the findings between baseline and before ST showed that the power densities of the alpha 1 and 2 bands tended to increase, whereas the theta power density increased significantly (P < .05). During NS, the power densities remained at a constant high level until after ST4. During SS and VS, the power densities were attenuated immediately to the same degree and maintained at a constant low level until after ST4.ConclusionsThis study is the first to demonstrate that EEG-measured arousal levels decrease within a short time during RAGT, but are restored and maintained by intermittent warning sound stimulation.

Effect of low molecular weight fish protein hydrolysate on growth performance and IGF-I expression in Japanese flounder (Paralichthys olivaceus) fed high plant protein diets

Seven isonitrogenous and isoenergetic experimental diets were formulated to investigate the effect of low molecular weight fish protein hydrolysate (FPH) in diets on growth performance, feed utilization and liver IGF-I mRNA levels in Japanese flounder (38.80 ± 1.11 g) fed with high plant protein diets. Fish meal protein was, respectively, replaced by 6% (FPH6), 11% (FPH11), 16% (FPH16), 21% (FPH21), 26% (FPH26) FPH of total dietary protein. FPH diets contained a constant high level of plant protein (690 g kg−1) from soybean meal. As a positive control diet, FM2 contained about 590 g kg−1 plant protein and 410 g kg−1 fish meal protein, while negative control diet FM1 contained about 690 g kg−1 plant protein and 310 g kg−1 fish meal protein. The expression levels of liver IGF-I mRNA were evaluated using real-time PCR normalized against the 18S rRNA gene. The results showed that moderate low molecular weight FPH (FPH11) improved growth performance and protein retention. Fish fed with FPH11 and control diet FM2 had similar growth and feed utilization, while high-level low molecular weight FPH did not improve growth performance and protein retention, and depressed liver IGF-I mRNA expression in Japanese flounder.

The Autoregulatory Feedback Loop of MicroRNA-21/Programmed Cell Death Protein 4/Activation Protein-1 (MiR-21/PDCD4/AP-1) as a Driving Force for Hepatic Fibrosis Development

Sustained activation of hepatic stellate cells (HSCs) leads to hepatic fibrosis, which is characterized by excessive collagen production, and for which there is no available drug clinically. Despite tremendous progress, the cellular activities underlying HSC activation, especially the driving force in the perpetuation stage, are only partially understood. Recently, microRNA-21 (miR-21) has been found to be prevalently up-regulated during fibrogenesis in different tissues, although its detailed role needs to be further elucidated. In the present study, miR-21 expression was examined in human cirrhotic liver samples and in murine fibrotic livers induced by thioacetamide or carbon tetrachloride. A dramatic miR-21 increase was noted in activated HSCs. We further found that miR-21 maintained itself at constant high levels by using a microRNA-21/programmed cell death protein 4/activation protein-1 (miR-21/PDCD4/AP-1) feedback loop. Disrupting this loop with miR-21 antagomir or AP-1 inhibitors significantly suppressed fibrogenic activities in HSCs and ameliorated liver fibrosis. In contrast, reinforcing this loop with small interfering RNA (siRNA) against PDCD4 promoted fibrogenesis in HSCs. Further analysis indicated that the up-regulated miR-21 promoted the central transforming growth factor-β (TGF-β) signaling pathway underlying HSC activation. In summary, we suggest that the miR-21/PDCD4/AP-1 autoregulatory loop is one of the main driving forces for hepatic fibrosis progression. Targeting this aberrantly activated feedback loop may provide a new therapeutic strategy and facilitate drug discovery against hepatic fibrosis.

Effects of pain level and pain variability on coping strategies of patients with dystonia

Patients with dystonia experience involuntary contraction of muscles that may produce painful, twisted postures. This study investigated effects of pain level and pain variability on coping behaviors and daily activities. We hypothesized that substantial changes in pain levels would have similar effects as constant high levels of pain, and expected to see modifications in coping styles for different types of pain. Fifty-eight dystonia patients from four different countries (US, Canada, England, and Australia) completed the Pain Interference and Coping with Health Injuries and Problems Scales.

SIMS analysis on austenitic stainless steel: The influence of type of oxide surface layer on hydrogen embrittlement

Abstract The surface oxide layer on nine different types of solution-annealed austenitic stainless steel (ASS) was evaluated by Secondary Ion Mass Spectrometry (SIMS). Tensile tests were conducted at 25 °C and −50 °C in hydrogen at 40 MPa and in air at atmospheric pressure. Relative reduction of area (RRA) was calculated accordingly. Additionally the martensite transformation curves were measured in air at −50 °C to evaluate the probability of the formation of α′ martensite nuclei. A linear relationship between RRA and the calculated probability of the nucleation of α′ martensite nuclei was found on samples represented by the following three oxides types; (a) thick oxide, (b) decaying sub-surface oxide and (c) thin surface oxides. However, type (d) with high constant oxide level down to 60 nm depth does not follow the trend. The observed variation of the oxide layer is linked to the variability of tensile test results.

Distribution of steroid- and dioxin-like activities between sediments, POCIS and SPMD in a French river subject to mixed pressures

The contamination of aquatic systems by endocrine disrupting chemicals (EDCs) is now a widely established fact. Nevertheless, there is still a scarcity of knowledge concerning the source, transport, fate and bioavailability of such active compounds. In the present study we assessed the distribution of estrogenic, (anti-)androgenic, pregnane X receptor-like (PXR) and dioxin-like activities between sediment and water compartments using a polar organic compound integrative sampler (POCIS) and a semi-permeable membrane device (SPMD) passive sampler in a river where sediment has been previously described as highly and multi-contaminated. We first confirmed the contamination pattern of this river sediment between 2004, 2009 and 2010 samples, suggesting that this river is subject to a constant high contamination level. However, we showed a different distribution pattern of these activities between compartments: estrogenic activity was mainly detected in POCIS extracts and to a lesser extent in sediment and SPMD extracts; anti-androgenic activities were mainly detected in SPMD and sediment extracts while no activity was detected in POCIS extracts; PXR-like activity was detected in all three investigated compartments, with POCIS > SPMD > sediment; dioxin-like activity was mainly found in the sediment and the SPMD extracts. Overall, partitioning of the biological activities was in accordance with physicochemical properties (e.g., log K ow) of typical known active chemicals in each bioassay. Furthermore, in order to establish whether the chemicals involved in these activities were similar between the compartments, we fractionated sediment, POCIS and SPMD extracts using a multi-step fractionation procedure. This highlighted differences in the nature of active chemicals between compartments. Altogether, our results support the need to consider different compartments in order to enhance exposure assessment.

INFLUENCE OF NITRATE LOAD ON SULFUR TRANSFORMATIONS IN THE RHIZOSPHERE OF Juncus effusus IN LABORATORY-SCALE CONSTRUCTED WETLANDS TREATING ARTIFICIAL DOMESTIC WASEWATER

Two laboratory-scale constructed wetlands planted with Juncus effusus were used to investigate the effect of nitrate load on the sulfur transformation dynamics related to the removal of organic carbon and ammonium. Organic carbon was removed at a constant high mean level of 80% (inflow of 25 mg/L total organic carbon), irrespective of the nitrate load. In contrast, sulfate reduction responded immediately to the presence or absence of nitrate in an opposing manner, indicating a high abundance of sulfate-reducing bacteria along with an inhibitory effect of nitrate on sulfur reduction. In general, sulfate reduction as well as nitrate reduction were at relatively high mean levels of 70% (inflow of 10 mg/L SO4

Twentieth-century changes in the genetic composition of Swedish field pea metapopulations.

Landrace crops are formed by local adaptation, genetic drift and gene flow through seed exchange. In reverse, the study of genetic structure between landrace populations can reveal the effects of these forces over time. We present here the analysis of genetic diversity in 40 Swedish field pea (Pisum sativum L.) populations, either available as historical seed samples from the late nineteenth century or as extant gene bank accessions assembled in the late twentieth century. The historical material shows constant high levels of within-population diversity, whereas the extant accessions show varying, and overall lower, levels of within-population diversity. Structure and principal component analysis cluster most accessions, both extant and historical, in groups after geographical origin. County-wise analyses of the accessions show that the genetic diversity of the historical accessions is largely overlapping. In contrast, most extant accessions show signs of genetic drift. They harbor a subset of the alleles found in the historical accessions and are more differentiated from each other. These results reflect how, historically present metapopulations have been preserved during the twentieth century, although as genetically isolated populations.

Daten zur Antibiotikaresistenzlage in Deutschland

In 2007, the Robert Koch Institute established the infrastructure for the national Antimicrobial Resistance Surveillance (ARS) system. Laboratories submit data of routine susceptibility testing of clinical samples from hospitals as well as from outpatient care settings in a standardized format to the Robert Koch Institute for central processing. The database for the period 2008–2011 comprises data of about 1.3 million samples from patients in hospital care and almost 800,000 samples from outpatients. Based on SIR interpretations of susceptibility, the trends of methicillin resistance of Staphylococcus aureus (MRSA) and cefotaxime non-susceptibility as an indicator of extended-spectrum beta-lactamases (ESBL) of Escherichia coli and Klebsiella pneumoniae were analyzed for four care settings or categories: hospital care, outpatient care, intensive care units, and isolates from blood cultures. After constant high levels of above 20%, the proportion of MRSA isolates showed a decline for the first time from 2010 to 2011 in hospital care overall, in intensive care units as well as in blood cultures; in outpatient care, MRSA proportions of about 13% were observed. Within the observed period, non-susceptibility to cefotaxime as an indicator of ESBL in E. coli showed an increasing trend in hospital care at a level above 10% in intensive care units, while cefotaxime non-susceptibility in K. pneumoniae was more frequent but without any trend. In outpatient care, the proportions of cefotaxime non-susceptibility increased year by year in both species resulting in nearly a doubling to 6%.

Energy-Dependent Modulation of Glucagon-Like Signaling inDrosophilavia the AMP-Activated Protein Kinase

Adipokinetic hormone (AKH) is the equivalent of mammalian glucagon, as it is the primary insect hormone that causes energy mobilization. In Drosophila, current knowledge of the mechanisms regulating AKH signaling is limited. Here, we report that AMP-activated protein kinase (AMPK) is critical for normal AKH secretion during periods of metabolic challenges. Reduction of AMPK in AKH cells causes a suite of behavioral and physiological phenotypes resembling AKH cell ablations. Specifically, reduced AMPK function increases life span during starvation and delays starvation-induced hyperactivity. Neither AKH cell survival nor gene expression is significantly impacted by reduced AMPK function. AKH immunolabeling was significantly higher in animals with reduced AMPK function; this result is paralleled by genetic inhibition of synaptic release, suggesting that AMPK promotes AKH secretion. We observed reduced secretion in AKH cells bearing AMPK mutations employing a specific secretion reporter, confirming that AMPK functions in AKH secretion. Live-cell imaging of wild-type AKH neuroendocrine cells shows heightened excitability under reduced sugar levels, and this response was delayed and reduced in AMPK-deficient backgrounds. Furthermore, AMPK activation in AKH cells increases intracellular calcium levels in constant high sugar levels, suggesting that the underlying mechanism of AMPK action is modification of ionic currents. These results demonstrate that AMPK signaling is a critical feature that regulates AKH secretion, and, ultimately, metabolic homeostasis. The significance of these findings is that AMPK is important in the regulation of glucagon signaling, suggesting that the organization of metabolic networks is highly conserved and that AMPK plays a prominent role in these networks.