Agricultural and ecological aspects of a sandy soil as affected by the application of municipal solid waste composts   总被引：1，自引：0，他引：1  

J. Weber  A. Karczewska  J. Drozd  M. Licznar  S. Licznar  E. Jamroz  A. Kocowicz 《Soil biology & biochemistry》2007,39(6):1294-1302

We present the results of a plot experiment in which the changes in physical, chemical and physico-chemical properties of a sandy soil were examined after amending the soil with two different composts produced from municipal solid wastes. Triticale (X Triticosecale), cultivated in a 3-y monoculture, was used as a test plant. Both composts differed in their concentrations of heavy metals. Composts were applied non-recurrently in the spring before sowing, at the rates of 18, 36, and 72 t dry matter ha⁻¹. The plots without fertilization, and those fertilized annually with mineral nitrogen (N), phosphorous (P), and potassium (K) were used as controls. Soil samples were collected 1 month after compost application, as well as each year after harvesting. Application of both composts improved soil physical properties, associated with increasing content of organic carbon (OC). Statistically significant increases of total porosity, field water capacity and amounts of plant-available water were found only in the short time after compost application. Despite the fact that soil OC content decreased with time, a C:N ratio clearly increased in the third year after compost application, which was explained by a depletion of N reserve. Both composts caused a large increase of plant-available P, K, and magnesium (Mg), which was observed during the entire period of the experiment. Beneficial changes were also observed in soil humic substances composition. These were confirmed by increased humic acids content and humic/fulvic acid ratios. Soil cation exchange capacity and base saturation increased in all plots amended with composts. This effect was still observed 1 year after compost application, while in the third year it remained significant only at the highest compost rates. Compost originating from industrial areas, even if applied in low amounts, caused a significant increase in total concentration of soil heavy metals. This fact did not result, however, in any substantial changes in soil quality with regard to heavy metals content.  相似文献   

Aging of combustion particles in the atmosphere — Results from a field study in Zürich     

H. Burtscher  A. Leonardi  D. Steiner  U. Baltensperger  A. Weber 《Water, air, and soil pollution》1993,68(1-2):137-147

At different locations in Zürich (urban and suburban area) ambient aerosol has been measured by a variety of methods. Total mass concentration, black carbon mass concentration, size distribution, Fuchs surface and photoelectric charging of particles (as a measure for the PAH concentration) have been determined. As a reference for “fresh” aerosol, measurements have also been carried out in a car parking garage. By comparing the data obtained at different locations and different times of the day aging processes can be investigated. All measured signals show significant peaks during the rush-hours, indicating that the majority of the particles arise from automotive traffic. Aging is expressed by decreasing number concentrations, increasing diameter (coagulation) and decreasing black carbon and PAH content of the particles. The decrease in PAH and black carbon fraction may be due to mixing of the aerosol with non-combustion particles or by condensation of material from the gas phase on the particle; the decrease in PAH concentration may also be due to degradation of the PAHs.  相似文献   

Rapid identification of nonessential genes of herpes simplex virus type 1 by Tn5 mutagenesis   总被引：27，自引：0，他引：27  

P C Weber  M Levine  J C Glorioso 《Science (New York, N.Y.)》1987,236(4801):576-579

The large genome of herpes simplex virus type of (HSV-1) encodes at least 80 polypeptides, the majority of which have no recognized function. A subgroup of these gene products appears to be nonessential for virus replication in cell culture, but contributes to the complex life cycle of the virus in the host. To identify such functions, a simple insertional mutagenesis method has been used for selective inactivation of individual HSV-1 genes. The bacterial transposon Tn5 was allowed to insert randomly into cloned restriction fragments representing the entire short unique (US) region of the HSV-1 genome. Of the 12 open reading frames that were mutagenized with Tn5, mutant derivatives of US2, US4, and US5 were recombined into the virus. These three genes proved to be nonessential for HSV-1 replication in Vero (African Green monkey kidney) cells and the US4 gene appeared to be involved in viral pathogenesis in the central nervous system of mice. This rapid mutagenesis procedure should prove useful in exploring the entire HSV-1 genome as well as the genomes of other complex animal viruses.  相似文献   

Slow deformation and lower seismic hazard at the new madrid seismic zone   总被引：1，自引：0，他引：1  

Newman A  Stein S  Weber J  Engeln J  Mao A  Dixon T 《Science (New York, N.Y.)》1999,284(5414):619-621

Global Positioning System (GPS) measurements across the New Madrid seismic zone (NMSZ) in the central United States show little, if any, motion. These data are consistent with platewide continuous GPS data away from the NMSZ, which show no motion within uncertainties. Both these data and the frequency-magnitude relation for seismicity imply that had the largest shocks in the series of earthquakes that occurred in 1811 and 1812 been magnitude 8, their recurrence interval should well exceed 2500 years, longer than has been assumed. Alternatively, the largest 1811 and 1812 earthquakes and those in the paleoseismic record may have been much smaller than typically assumed. Hence, the hazard posed by great earthquakes in the NMSZ appears to be overestimated.  相似文献   

Conserved folding in retroviral proteases: crystal structure of a synthetic HIV-1 protease   总被引：57，自引：0，他引：57  

A Wlodawer  M Miller  M Jaskólski  B K Sathyanarayana  E Baldwin  I T Weber  L M Selk  L Clawson  J Schneider  S B Kent 《Science (New York, N.Y.)》1989,245(4918):616-621

The rational design of drugs that can inhibit the action of viral proteases depends on obtaining accurate structures of these enzymes. The crystal structure of chemically synthesized HIV-1 protease has been determined at 2.8 angstrom resolution (R factor of 0.184) with the use of a model based on the Rous sarcoma virus protease structure. In this enzymatically active protein, the cysteines were replaced by alpha-amino-n-butyric acid, a nongenetically coded amino acid. This structure, in which all 99 amino acids were located, differs in several important details from that reported previously by others. The interface between the identical subunits forming the active protease dimer is composed of four well-ordered beta strands from both the amino and carboxyl termini and residues 86 to 94 have a helical conformation. The observed arrangement of the dimer interface suggests possible designs for dimerization inhibitors.  相似文献   

Evidence for Alfvén waves in solar x-ray jets     

Cirtain JW  Golub L  Lundquist L  van Ballegooijen A  Savcheva A  Shimojo M  Deluca E  Tsuneta S  Sakao T  Reeves K  Weber M  Kano R  Narukage N  Shibasaki K 《Science (New York, N.Y.)》2007,318(5856):1580-1582

Coronal magnetic fields are dynamic, and field lines may misalign, reassemble, and release energy by means of magnetic reconnection. Giant releases may generate solar flares and coronal mass ejections and, on a smaller scale, produce x-ray jets. Hinode observations of polar coronal holes reveal that x-ray jets have two distinct velocities: one near the Alfvén speed ( approximately 800 kilometers per second) and another near the sound speed (200 kilometers per second). Many more jets were seen than have been reported previously; we detected an average of 10 events per hour up to these speeds, whereas previous observations documented only a handful per day with lower average speeds of 200 kilometers per second. The x-ray jets are about 2 x 10(3) to 2 x 10(4) kilometers wide and 1 x 10(5) kilometers long and last from 100 to 2500 seconds. The large number of events, coupled with the high velocities of the apparent outflows, indicates that the jets may contribute to the high-speed solar wind.  相似文献   

Spread of HTLV-I between lymphocytes by virus-induced polarization of the cytoskeleton     

Igakura T  Stinchcombe JC  Goon PK  Taylor GP  Weber JN  Griffiths GM  Tanaka Y  Osame M  Bangham CR 《Science (New York, N.Y.)》2003,299(5613):1713-1716

Cell contact is required for efficient transmission of human T cell leukemia virus- type 1 (HTLV-I) between cells and between individuals, because naturally infected lymphocytes produce virtually no cell-free infectious HTLV-I particles. However, the mechanism of cell-to-cell spread of HTLV-I is not understood. We show here that cell contact rapidly induces polarization of the cytoskeleton of the infected cell to the cell-cell junction. HTLV-I core (Gag protein) complexes and the HTLV-I genome accumulate at the cell-cell junction and are then transferred to the uninfected cell. Other lymphotropic viruses, such as HIV-1, may similarly subvert normal T cell physiology to allow efficient propagation between cells.  相似文献   

Feedback inhibition of key glycolytic enzymes in liver: action of free fatty acids   总被引：12，自引：0，他引：12  

G Weber  H J Convery  M A Lea  N B Stamm 《Science (New York, N.Y.)》1966,154(754):1357-1360

Increasing concentrations of sodium octanoate were progressively inhibitory to the activities of glucokinase, hexokinase, phosphofructokinase, and pyruvate kinase. Glucose-6-phosphate and 6-phosphogluconate dehydrogenases were also markedly inhibited. Other enzymes of carbohydrate metabolism such as lactate dehydrogenase, phosphohexose isomerase, and fructose-1,6-diphosphatase were not decreased. Among the key glycolytic enzymes, the inhibition of pyruvate kinase by the fatty acid was most marked. The biological significance of the inhibition of the key glycolytic enzymes is interpreted as a feedback inhibitory mechanism in regulation of fatty acid biosynthesis. The mechanism may function for rapid adaptation by which the organism can use the fatty acid level as a metabolic directional switch in decreasing glycolysis and turning on gluconeogenesis.  相似文献   

Peroxidase and resistance to ceratocystis in sweet potato increased by volatile materials   总被引：2，自引：0，他引：2  

B Clare  D J Weber  M A Stahmann 《Science (New York, N.Y.)》1966,153(731):62-63

Increased peroxidase activity and resistance to black rot was found in sweet potato roots incubated above infected roots in closed containers when compared with similar tissue incubated above uninfected roots. The peroxidase increases were detected in unpurified extracts and in extracts subjected to gel electrophoresis.  相似文献   

A persistent oxygen anomaly reveals the fate of spilled methane in the deep Gulf of Mexico   总被引：3，自引：0，他引：3  

Kessler JD  Valentine DL  Redmond MC  Du M  Chan EW  Mendes SD  Quiroz EW  Villanueva CJ  Shusta SS  Werra LM  Yvon-Lewis SA  Weber TC 《Science (New York, N.Y.)》2011,331(6015):312-315

Methane was the most abundant hydrocarbon released during the 2010 Deepwater Horizon oil spill in the Gulf of Mexico. Beyond relevancy to this anthropogenic event, this methane release simulates a rapid and relatively short-term natural release from hydrates into deep water. Based on methane and oxygen distributions measured at 207 stations throughout the affected region, we find that within ~120 days from the onset of release ~3.0 × 10(10) to 3.9 × 10(10) moles of oxygen were respired, primarily by methanotrophs, and left behind a residual microbial community containing methanotrophic bacteria. We suggest that a vigorous deepwater bacterial bloom respired nearly all the released methane within this time, and that by analogy, large-scale releases of methane from hydrate in the deep ocean are likely to be met by a similarly rapid methanotrophic response.  相似文献