Closing the methane mass balance for an old closed Danish landfill.

In this study, a methane (CH4) mass balance was established for Hedeland landfill. CH4 generation rates were modelled using a multiphase first-order decay model (The Afvalzorg model) and determined at between 57 and 79 kg h-1. The CH4 emission rate was quantified at between 2 and 14 kg h-1, using the tracer gas dispersion method and the CH4 gas recovery efficiency was between 8 and 21%. At three places along the perimeter of the landfill, gas remediation systems have been installed to protect the residential houses from any risk of migrating landfill gas. About 0.76 kg h-1 of CH4 was extracted from these three remediation systems. Using a carbon mass balance for the lateral migrating landfill gas showed a fractional oxidation of about 78%, which corresponded to a CH4 flux of 3.5 kg h-1 from the three remediation systems, including the oxidised CH4. The total lateral CH4 flux (un-oxidised) from the total landfill perimeter was estimated at between 6.9 and 10.4 kg h-1. CH4 oxidation efficiency in the landfill cover soil, determined from stable carbon isotope analyses, was found to be between 12% and 92%. This resulted in an average CH4 oxidation rate of 32 kg h-1, using an average CH4 emission rate of 8 kg h-1. CH4 surface screenings and surface flux measurements supported the hypothesis that oxidation efficiency was in the higher range and that oxidation could close the CH4 mass balance.

Biofiltration of diluted landfill gas in an active loaded open-bed compost filter.

Microbial oxidation in a biofilter is a treatment solution for diluted landfill gas (LFG), for instance at old landfills, where LFG recovery is no longer feasible, or from remediation systems designed to cut off laterally migrating LFG. In this study, an actively loaded open-bed compost filter, designed for the treatment of diluted LFG, was tested at an old landfill in Denmark. An 18 m3 biofilter was constructed in a 30 m3 container loaded with LFG mixed with air, in order to obtain diluted LFG. The inlet concentration of methane (CH4) fluctuated between 4.4 and 9.2 vol% during the five tested flow campaigns, resulting in CH4 loads of 106-794 g CH4 m-2 d-1. The maximum identified CH4 oxidation rate was 460 g m-2 d-1, with an overall CH4 oxidation efficiency of 58%. Due to preferential flows, especially along the edges of the filter at the transition points between the compost and the container wall, an overall CH4 oxidation efficiency of 100% was never achieved. However, pore gas profiles in selected areas in the filter material showed oxidation efficiencies close to 100%. The results were supported by tracer gas tests showing average oxidation efficiency in the nine measuring points of 89% at a CH4 load of 487 ± 64 g CH4 m-2 d-1.

Assessment of a landfill methane emission screening method using an unmanned aerial vehicle mounted thermal infrared camera - A field study.

An unmanned aerial vehicle (UAV)-mounted thermal infrared (TIR) camera's ability to delineate landfill gas (LFG) emission hotspots was evaluated in a field test at two Danish landfills (Hedeland landfill and Audebo landfill). At both sites, a test area of 100 m2 was established and divided into about 100 measuring points. The relationship between LFG emissions and soil surface temperatures were investigated through four to five measuring campaigns, in order to cover different atmospheric conditions along with increasing, decreasing and stable barometric pressure. For each measuring campaign, a TIR image of the test area was obtained followed by the measurement of methane (CH4) and carbon dioxide (CO2) emissions at each measuring point, using a static flux chamber. At the same time, soil temperatures measured on the surface, at 5 cm and 10 cm depths, were registered. At the Hedeland landfill, no relationship was found between LFG emissions and surface temperatures. In addition, CH4 emissions were very limited, on average 0.92-4.52 g CH4 m-2 d-1, and only measureable on the two days with decreasing barometric pressure. TIR images from Hedeland did not show any significant temperature differences in the test area. At the Audebo landfill, an area with slightly higher surface temperatures was found in the TIR images, and the same pattern with slightly higher temperatures was found at a depth of 10 cm. The main LFG emissions were found in the area with the higher surface temperatures. LFG emissions at Audebo were influenced significantly by changes in barometric pressure, and the average CH4 emissions varied between 111 g m-2 d-1 and 314 g m-2 d-1, depending on whether the barometric pressure gradient had increased or decreased, respectively. The temperature differences observed in the TIR images from both landfills were limited to between 0.7 °C and 1.2 °C. The minimum observable CH4 emission for the TIR camera to identify an emission hotspot was 150 g CH4 m-2 d-1 from an area of more than 1 m2.

Is negative self-referent bias an endophenotype for depression? An fMRI study of emotional self-referent words in twins at high vs. low risk of depression.

BACKGROUND: Negative cognitive bias and aberrant neural processing of self-referent emotional words seem to be trait-marks of depression. However, it is unclear whether these neurocognitive changes are present in unaffected first-degree relatives and constitute an illness endophenotype. METHODS: Fifty-three healthy, never-depressed monozygotic or dizygotic twins with a co-twin history of depression (high-risk group: n = 26) or no first-degree family history of depression (low-risk group: n = 27) underwent neurocognitive testing and functional magnetic imaging (fMRI) as part of a follow-up cohort study. Participants performed a self-referent emotional word categorisation task and free word recall task followed by a recognition task during fMRI. Participants also completed questionnaires assessing mood, personality traits and coping strategies. RESULTS: High-risk and low-risk twins (age, mean ± SD: 40 ± 11) were well-balanced for demographic variables, mood, coping and neuroticism. High-risk twins showed lower accuracy during self-referent categorisation of emotional words independent of valence and more false recollections of negative words than low-risk twins during free recall. Functional MRI yielded no differences between high-risk and low-risk twins in retrieval-specific neural activity for positive or negative words or during the recognition of negative versus positive words within the hippocampus or prefrontal cortex. CONCLUSIONS: The subtle display of negative recall bias is consistent with the hypothesis that self-referent negative memory bias is an endophenotype for depression. High-risk twins' lower categorisation accuracy adds to the evidence for valence-independent cognitive deficits in individuals at familial risk for depression.

Ras regulates kinesin 13 family members to control cell migration pathways in transformed human bronchial epithelial cells.

We show that expression of the microtubule depolymerizing kinesin KIF2C is induced by transformation of immortalized human bronchial epithelial cells (HBEC) by expression of K-Ras(G12V) and knockdown of p53. Further investigation demonstrates that this is due to the K-Ras/ERK1/2 MAPK pathway, as loss of p53 had little effect on KIF2C expression. In addition to KIF2C, we also found that the related kinesin KIF2A is modestly upregulated in this model system; both proteins are expressed more highly in many lung cancer cell lines compared to normal tissue. As a consequence of their depolymerizing activity, these kinesins increase dynamic instability of microtubules. Depletion of either of these kinesins impairs the ability of cells transformed with mutant K-Ras to migrate and invade matrigel. However, depletion of these kinesins does not reverse the epithelial to mesenchymal transition (EMT) caused by mutant K-Ras. Our studies indicate that increased expression of microtubule destabilizing factors can occur during oncogenesis to support enhanced migration and invasion of tumor cells.

NeuroD1 regulation of migration accompanies the differential sensitivity of neuroendocrine carcinomas to TrkB inhibition.

The developmental transcription factor NeuroD1 is anomalously expressed in a subset of aggressive neuroendocrine tumors. Previously, we demonstrated that TrkB and neural cell adhesion molecule (NCAM) are downstream targets of NeuroD1 that contribute to the actions of neurogenic differentiation 1 (NeuroD1) in neuroendocrine lung. We found that several malignant melanoma and prostate cell lines express NeuroD1 and TrkB. Inhibition of TrkB activity decreased invasion in several neuroendocrine pigmented melanoma but not in prostate cell lines. We also found that loss of the tumor suppressor p53 increased NeuroD1 expression in normal human bronchial epithelial cells and cancer cells with neuroendocrine features. Although we found that a major mechanism of action of NeuroD1 is by the regulation of TrkB, effective targeting of TrkB to inhibit invasion may depend on the cell of origin. These findings suggest that NeuroD1 is a lineage-dependent oncogene acting through its downstream target, TrkB, across multiple cancer types, which may provide new insights into the pathogenesis of neuroendocrine cancers.

Genetic association study of CYP1A1 polymorphisms identifies risk haplotypes in nonsmall cell lung cancer.

Lung cancer remains a leading cause of disease globally, with smoking being the largest single cause. Phase I enzymes, including cytochrome P(450), family 1, subfamily A, polypeptide 1 (CYP1A1), are involved in the activation of carcinogens, such as polycyclic aromatic hydrocarbons, to reactive intermediates that are capable of binding covalently to DNA to form DNA adducts, potentially initiating the carcinogenic process. The aim of the present study was to investigate the association of CYP1A1 gene polymorphisms and haplotypes with lung cancer risk. A case-control study was carried out on 1,040 nonsmall cell lung cancer (NSCLC) cases and 784 controls to investigate three CYP1A1 variants, CYP1A1*2A (rs4646903; thymidine to cytosine substitution at nucleotide 3801 (3801T>C)), CYP1A1*2C (rs1048943; 2455A>G; substitution of isoleucine 462 with valine (exon 7)) and CYP1A1*4 (rs1799814; 2453C>A; substitution of threonine 461 with asparagine (exon 7)) using PCR restriction fragment length polymorphism methods. The CYP1A1*2A and CYP1A1*2C variants were significantly over-represented in NSCLC cases compared with controls, whereas the CYP1A1*4 variant was under-represented. CYP1A1 haplotypes (in allele order CYP1A1*4, CYP1A1*2C, CYP1A1*2A) CGC and CGT were associated with an increased risk of lung cancer, whereas AAT was associated with decreased lung cancer risk in this population. The present study has identified risk haplotypes for CYP1A1 in NSCLC and confirmed that CYP1A1 polymorphisms are a minor risk factor for NSCLC.

Region and Field Level Distributions of Aster Yellows Phytoplasma in Small Grain Crops.

Aster yellows (AY), a disease of small grain crops caused by aster yellows phytoplasma (AYp), produces disease symptoms similar to barley yellow dwarf (BYD). From 2003 to 2005, small grain production fields in Minnesota and North Dakota were surveyed to determine the incidences of AY and BYD. In-field spatial patterns of AY-infected plants also were investigated. Plants collected along a five-point transect line were tested for AYp using nested polymerase chain reaction (PCR) and quantitative real-time PCR assays, and extracted plant sap was tested for serotypes PAV and RPV of Barley yellow dwarf virus (BYDV) using enzyme-linked immunosorbent assays. During 2003, 2004, and 2005, AYp was detected in plants from 49, 15, and 7% of tested fields, respectively, whereas BYDV was found in plants from 2, 0, and 5% of fields, respectively. Average amplicon count number indicated an in-field spatial trend for greater incidence of AYp and increased populations of AYp in plants located near field edges, with comparably low copy numbers at transect point locations toward the direction of field center. AY is likely a common but largely undetected disease on small grain crops in the Upper Midwest.

Gene expression of lung squamous cell carcinoma reflects mode of lymph node involvement.

Tumour, node, metastasis staging is essential for lung cancer management. However, similarly staged cancers may have markedly different prognoses, indicating that stage cannot completely explain tumour behaviour. While ipsilateral hilar node involvement is designated N1, the current authors hypothesised that primary tumours involving nodes by direct extension are biologically distinct from those involving nodes through lymphatic metastasis. Microarrays were used to investigate the gene expression profiles of 59 primary lung squamous cell carcinomas, comparing N0 tumours (n = 35), N1 tumours by direct extension (N1d; n = 8), and N1/N2 tumours by lymphatic metastasis (N1/N2m; n = 16). Hierarchical clustering using 125 genes differentially expressed between N0 and N1/N2m tumours found N1d tumours clustered with N0 tumours. Class prediction modelling found the expression profiles of all eight N1d tumours were more similar to N0 than to N1/N2m tumours. The present study demonstrates for the first time that N1 tumours directly invading hilar nodes are genomically different to those that metastasise via lymphatics. Independent reports suggest that tumours with direct, rather than metastatic node involvement have better outcomes. Consequently, the data suggest that there is a need to re-evaluate the N1 staging definition in lung cancer. This is relevant for prognosis prediction and also for clinical management, particularly in selecting those patients most likely to benefit from adjuvant chemotherapy.

Distribution of Phoma sclerotioides on Alfalfa and Winter Wheat Crops in the North Central United States.

Brown root rot of alfalfa (Medicago sativa), caused by Phoma sclerotioides, has been reported in several states in the northern United States and in western Canada. A survey was conducted to determine the distribution of the fungus in Minnesota and Wisconsin. Isolates of the pathogen were recovered from roots of alfalfa, winter wheat, and perennial ryegrass plants. The internal transcribed spacer (ITS) 1, 5.8S, and ITS2 of the rDNA of the isolates from alfalfa and wheat were identical and matched the sequences of a P. sclerotioides isolate from Wyoming. The fungus was found to be widespread in both states and was detected in roots of alfalfa plants from 17 counties in Minnesota and 14 counties in Wisconsin using polymerase chain reaction (PCR)-based assays. A real-time PCR assay was developed that increased sensitivity of detecting the pathogen from plant tissues and soil. The isolates from alfalfa caused disease on inoculated winter wheat plants. Although the fungus was previously found associated with roots of diseased cereal and turfgrass plants, this is the first demonstration of pathogenicity of P. sclerotioides on wheat.

Apical and non-polarized secretion of serpins from MDCK cells.

Corticosteroid binding globulin, a member of the serpin family, was previously shown to be secreted mainly apically from MDCK cells in an N-glycan independent manner [Larsen et al. (1999) FEBS Lett. 451, 19-22]. Apart from N-glycosylation, serpins are not known to carry any other posttranslational modifications, suggesting the presence of a proteinaceous apical sorting signal. In the present study we have expressed four other members of the serpin family: alpha1-antitrypsin, C1 inhibitor, plasminogen activator inhibitor-1 and antithrombin in MDCK cells. Tight monolayers of transfected cells were grown on filters and the amounts of recombinantly expressed serpins in the apical and the basolateral media were determined. alpha1-Antitrypsin and C1 inhibitor were found mainly in the apical medium whereas plasminogen activator inhibitor-1 and antithrombin were found in roughly equal amounts in the apical and basolateral media. Control experiments showed that all four serpins are transported along the exocytotic pathway in an uncomplicated way that does not involve transcytosis or differences in stability on the two sides of the cells. We conclude that some members of the serpin family including corticosteroid binding globulin, alpha1-antitrypsin and C1 inhibitor are secreted mainly apically from MDCK cells whereas plasminogen activator inhibitor-1 and antithrombin are secreted in a non-polarized manner.

Pax gene diversity in the basal cnidarian Acropora millepora (Cnidaria, Anthozoa): implications for the evolution of the Pax gene family.

Pax genes encode a family of transcription factors, many of which play key roles in animal embryonic development but whose evolutionary relationships and ancestral functions are unclear. To address these issues, we are characterizing the Pax gene complement of the coral Acropora millepora, an anthozoan cnidarian. As the simplest animals at the tissue level of organization, cnidarians occupy a key position in animal evolution, and the Anthozoa are the basal class within this diverse phylum. We have identified four Pax genes in Acropora: two (Pax-Aam and Pax-Bam) are orthologs of genes identified in other cnidarians; the others (Pax-Cam and Pax-Dam) are unique to Acropora. Pax-Aam may be orthologous with Drosophila Pox neuro, and Pax-Bam clearly belongs to the Pax-2/5/8 class. The Pax-Bam Paired domain binds specifically and preferentially to Pax-2/5/8 binding sites. The recently identified Acropora gene Pax-Dam belongs to the Pax-3/7 class. Clearly, substantial diversification of the Pax family occurred before the Cnidaria/higher Metazoa split. The fourth Acropora Pax gene, Pax-Cam, may correspond to the ancestral vertebrate Pax gene and most closely resembles Pax-6. The expression pattern of Pax-Cam, in putative neurons, is consistent with an ancestral role of the Pax family in neural differentiation and patterning. We have determined the genomic structure of each Acropora Pax gene and show that some splice sites are shared both between the coral genes and between these and Pax genes in triploblastic metazoans. Together, these data support the monophyly of the Pax family and indicate ancient origins of several introns.

N-glycans are not the signal for apical sorting of corticosteroid binding globulin in MDCK cells.

It has been suggested that N-glycans act as a general sorting signal for secretory proteins in MDCK cells [Scheiffele et al. (1995) Nature 378, 96-98]. Human corticosteroid binding globulin contains six consensus sites for N-glycosylation and is known to be secreted to the apical side of MDCK cells. Our results show that wild-type corticosteroid binding globulin is N-glycosylated when it is recombinantly expressed in MDCK cells. Six mutants, each lacking one of the N-glycosylation sites, and a mutant lacking all six N-glycosylation sites were also secreted to the apical side of MDCK cells in a polarized manner. Thus, the N-glycans on corticosteroid binding globulin do not act as an apical sorting signal in MDCK cells.

Aging and episodic memory: are elderly adults less likely to make connections between target and contextual information?

The hypothesis that elderly individuals are less likely than young adults to connect target and contextual information was tested. Young and elderly adults were presented with a number of slides, each of which contained a word superimposed in the center of a background picture of a landscape or cityscape. Half of the subjects were told to remember the words and half were told to remember the word-and-background pairs. All subjects were then tested for their recognition memory of the word-and-background pairs. The results indicate that elderly adults have greater difficulty than young adults remembering the connections between words and background pictures but that this occurs whether the pictures are target information or contextual information. Therefore, the results of this study provide no support for the notion that elderly adults have a specific contextual encoding deficit.

Processing yields and meat flavor of broilers fed a mixture of narasin and nicarbazin as an anticoccidial agent.

Processed yields (percent hot carcass) and cooked meat flavor of broilers fed 100 ppm of an anticoccidial agent (a mixture of 50 ppm narasin and 50 ppm nicarbazin) were compared with yields of birds fed a ration without the anticoccidial agent. Broilers were processed at 7 wk of age (49 days) after a 4-day withdrawal from the anticoccidial agent for the treated birds. The flavor of meat was evaluated by a 12-member sensory panel. Meat was either deep fat-fried or oven roasted. Sensory evaluations were made on freshly cooked samples and on cooked meat refrigerated for 24 h and reheated. The anticoccidial agent did not produce a difference (P greater than .05) in the hot carcass yields of the broilers as compared with control birds fed the nonmedicated diet. Analyses of triangle test data for flavor evaluations by two statistical methods indicated that there were no detectable differences (P greater than .05) in flavor between broilers fed the anticoccidial agent in the diet and those fed the control diet.

Analysis of the terminator region after the deoCABD operon of Escherichia coli K-12 using a new class of single copy number operon-fusion vectors.

We describe the construction of low copy number operon-fusion vectors, and use one of these vectors for the cloning and transcriptional analysis of the terminator region after the deo operon of Escherichia coli K-12. The new vectors are miniderivatives of plasmid R1 containing the parB stability locus of this plasmid and the lac genes as a selectable marker. Since the copy number of the vectors is only one per genome-equivalent at temperatures below 37 degrees C this system is ideally suited for isolation and characterization of transcriptional and translational signals from E. coli. Our results show that a very strong terminator (deot), which resembles Rho-independent terminators, is located 60 bp downstream from the fourth structural gene of the deo operon. This confirms that deoD is the last gene in the operon. In addition, we have identified a new promoter just after the deot terminator and a short DNA sequence that is able to reduce lacZ expression by 85% when inserted between the deoP2 promoter and the lac genes.

Long-range cooperativity between gene regulatory sequences in a prokaryote.

Regulation of transcription initiation by proteins binding at DNA sequences some distance from the promoter region itself seems to be a general phenomenon in both eukaryotes and prokaryotes. Proteins bound to an enhancer site in eukaryotes can turn on a distant gene, whereas efficient repression of some prokaryotic genes such as the gal, ara and deo operons of Escherichia coli, requires the presence of two operator sites, separated by 110, 200 and 600 base pairs (bp) respectively. In the deo operon, which encodes nucleoside catabolizing enzymes, we have shown that efficient and cooperative repression can be obtained when the distance between the two sites ranges from 224 to 997 bp. Here, we report that transcription initiation can be regulated from an operator site placed 1 to 5 kilobases (kb) downstream of the deoP2 promoter (and downstream of the transcribed gene), and present the first experimental data for prokaryotic regulation at distances greater than 1 kb. Our results support the model of DNA loop formation as a common regulatory mechanism explaining both some prokaryotic regulation and the action of eukaryotic enhancers.

Growth, feed conversions, and yields of turkey parts of three strains of hen turkeys as influenced by age.

Effects of age on the growth, feed to gain ratios, individual part weights, and yields of hen turkeys were determined weekly from ages 12 to 21 weeks. Two hundred birds from each of three strains (A, B, and C) were processed. All three strains of hen turkeys continued to gain weight throughout the study. During the 12 to 21-week-old period birds grew from an average of 4.76 kg to 9.17 kg, while the cumulative feed to gain ratios went from 1.97 to 2.94. Strain B consistently weighed more than Strains A and C for the duration of the study. Weights of all parts increased as hens grew larger. However, the parts' proportion of total weight changed. Percentages of breast, breast muscle, and fat increase, while percentages of wing, drumstick, and skin decreased. Breast, breast muscle, and fat yields increased from 32.8 to 35.9%, 23.8 to 28.0%, and 1.7 to 5.1%, respectively. Both wing and drumstick percentages declined from approximately 14.0 to 12.0%. Thigh, thigh muscle, and shell percentages varied, but ended near their starting levels, of 14.8, 10.5, and 21.8%, respectively. At 21 weeks of age the hen turkeys were still gaining body weight. Breast weight--both actual and percentages--were still increasing.